Concept-wise Practice

quadratic-roots MCQ Questions for Class 10

quadratic-roots se related questions ko ek jagah revise karein. Har question me bilingual content, answer feedback aur explanation available hai.

Practice Questions

200 questions tagged with quadratic-roots.

यदि \(3x^2+2x+\lambda=0\) की जड़ें वास्तविक नहीं हैं, तो \(\lambda\) पर सही शर्त क्या है?

If the roots of \(3x^2+2x+\lambda=0\) are not real, what is the correct condition on \(\lambda\)?

Explanation opens after your attempt
Correct Answer

A. \(\lambda>\frac{1}{3}\)

Step 1

Concept

For non-real roots, (D<0) is required. From \(4-12\lambda<0\), we get \(\lambda>\frac{1}{3}\).

Step 2

Why this answer is correct

The correct answer is A. \(\lambda>\frac{1}{3}\). For non-real roots, (D<0) is required. From \(4-12\lambda<0\), we get \(\lambda>\frac{1}{3}\).

Step 3

Exam Tip

वास्तविक नहीं होने के लिए (D<0) चाहिए। \(4-12\lambda<0\) से \(\lambda>\frac{1}{3}\) मिलता है।

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यदि \(x^2-6x+n=0\) की जड़ें \(\alpha,\beta\) हैं और \(\alpha^2+\beta^2=20\), तो (n) का मान क्या है?

If \(\alpha,\beta\) are the roots of \(x^2-6x+n=0\) and \(\alpha^2+\beta^2=20\), what is the value of (n)?

Explanation opens after your attempt
Correct Answer

A. (8)

Step 1

Concept

Here \(\alpha+\beta=6\) and \(\alpha\beta=n\). From (36-2n=20), we get (n=8).

Step 2

Why this answer is correct

The correct answer is A. (8). Here \(\alpha+\beta=6\) and \(\alpha\beta=n\). From (36-2n=20), we get (n=8).

Step 3

Exam Tip

\(\alpha+\beta=6\) और \(\alpha\beta=n\) है। (36-2n=20) से (n=8) मिलता है।

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(x-2-2(a+1)x+a-2-1=0) की जड़ों का गुणनफल (0) हो, तो (a) का कौन-सा मान संभव है?

If the product of the roots of (x-2-2(a+1)x+a-2-1=0) is (0), which value of (a) is possible?

Explanation opens after your attempt
Correct Answer

A. (1) या (-1)(1) or (-1)

Step 1

Concept

The product of roots is \(a^2-1\). Setting it equal to (0) gives \(a^2=1\), so (a=1) or (a=-1).

Step 2

Why this answer is correct

The correct answer is A. (1) या (-1) / (1) or (-1). The product of roots is \(a^2-1\). Setting it equal to (0) gives \(a^2=1\), so (a=1) or (a=-1).

Step 3

Exam Tip

जड़ों का गुणनफल \(a^2-1\) है। इसे (0) रखने पर \(a^2=1\), इसलिए (a=1) या (a=-1)।

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यदि \(x^2+ax+b=0\) की जड़ें \(\frac{1}{2+\sqrt{3}}\) और \(\frac{1}{2-\sqrt{3}}\) हैं, तो (a) का मान क्या है?

If the roots of \(x^2+ax+b=0\) are \(\frac{1}{2+\sqrt{3}}\) and \(\frac{1}{2-\sqrt{3}}\), what is the value of (a)?

Explanation opens after your attempt
Correct Answer

A. (-4)

Step 1

Concept

The given roots become \(2-\sqrt{3}\) and \(2+\sqrt{3}\). Their sum is (4), so (a=-4).

Step 2

Why this answer is correct

The correct answer is A. (-4). The given roots become \(2-\sqrt{3}\) and \(2+\sqrt{3}\). Their sum is (4), so (a=-4).

Step 3

Exam Tip

दी गई जड़ें \(2-\sqrt{3}\) और \(2+\sqrt{3}\) बनती हैं। उनका योग (4) है, इसलिए (a=-4)।

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यदि \(x^2-2x+k=0\) की जड़ें \(\tan \theta\) और \(\cot \theta\) हैं, तो (k) का मान क्या है?

If the roots of \(x^2-2x+k=0\) are \(\tan \theta\) and \(\cot \theta\), what is the value of (k)?

Explanation opens after your attempt
Correct Answer

A. (1)

Step 1

Concept

We know \(\tan \theta\cdot\cot \theta=1\). The product of roots is (k), so (k=1).

Step 2

Why this answer is correct

The correct answer is A. (1). We know \(\tan \theta\cdot\cot \theta=1\). The product of roots is (k), so (k=1).

Step 3

Exam Tip

\(\tan \theta\cdot\cot \theta=1\) होता है। जड़ों का गुणनफल (k) है, इसलिए (k=1)।

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यदि \(x^2-4x+k=0\) की जड़ें \(\sin \theta\) और \(\cos \theta\) हैं, तो (k) का अधिकतम संभव मान क्या है?

If the roots of \(x^2-4x+k=0\) are \(\sin \theta\) and \(\cos \theta\), what is the maximum possible value of (k)?

Explanation opens after your attempt
Correct Answer

A. ऐसा कोई वास्तविक \(\theta\) नहींNo such real \(\theta\)

Step 1

Concept

We would need \(\sin \theta+\cos \theta=4\), but its maximum is \(\sqrt{2}\). Therefore no real \(\theta\) is possible.

Step 2

Why this answer is correct

The correct answer is A. ऐसा कोई वास्तविक \(\theta\) नहीं / No such real \(\theta\). We would need \(\sin \theta+\cos \theta=4\), but its maximum is \(\sqrt{2}\). Therefore no real \(\theta\) is possible.

Step 3

Exam Tip

\(\sin \theta+\cos \theta=4\) होना पड़ेगा, पर इसका अधिकतम \(\sqrt{2}\) है। इसलिए ऐसा वास्तविक \(\theta\) संभव नहीं है।

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यदि \(x^2-9x+18=0\) की जड़ें \(\alpha,\beta\) हैं, तो \(\frac{\alpha}{\beta}+\frac{\beta}{\alpha}\) का मान क्या है?

If \(\alpha,\beta\) are the roots of \(x^2-9x+18=0\), what is \(\frac{\alpha}{\beta}+\frac{\beta}{\alpha}\)?

Explanation opens after your attempt
Correct Answer

A. \(\frac{5}{2}\)

Step 1

Concept

We use \(\frac{\alpha}{\beta}+\frac{\beta}{\alpha}=\frac{\alpha^2+\beta^2}{\alpha\beta}\). Here \(\alpha^2+\beta^2=45\) and \(\alpha\beta=18\), so the value is \(\frac{5}{2}\).

Step 2

Why this answer is correct

The correct answer is A. \(\frac{5}{2}\). We use \(\frac{\alpha}{\beta}+\frac{\beta}{\alpha}=\frac{\alpha^2+\beta^2}{\alpha\beta}\). Here \(\alpha^2+\beta^2=45\) and \(\alpha\beta=18\), so the value is \(\frac{5}{2}\).

Step 3

Exam Tip

\(\frac{\alpha}{\beta}+\frac{\beta}{\alpha}=\frac{\alpha^2+\beta^2}{\alpha\beta}\) है। यहाँ \(\alpha^2+\beta^2=45\) और \(\alpha\beta=18\), इसलिए मान \(\frac{5}{2}\) है।

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(x-2-(2a+1)x+a(a+1)=0) की जड़ों के बारे में सही निष्कर्ष क्या है?

What is the correct conclusion about the roots of (x-2-(2a+1)x+a(a+1)=0)?

Explanation opens after your attempt
Correct Answer

A. जड़ें (a) और (a+1) हैंThe roots are (a) and (a+1)

Step 1

Concept

The sum of roots is (2a+1) and the product is (a(a+1)). These match the pair (a) and (a+1).

Step 2

Why this answer is correct

The correct answer is A. जड़ें (a) और (a+1) हैं / The roots are (a) and (a+1). The sum of roots is (2a+1) and the product is (a(a+1)). These match the pair (a) and (a+1).

Step 3

Exam Tip

जड़ों का योग (2a+1) और गुणनफल (a(a+1)) है। ये (a) और (a+1) की योग-गुणनफल जोड़ी से मेल खाते हैं।

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यदि (x-2-(m+2)x+3m=0) की एक जड़ (3) है, तो दूसरी जड़ क्या है?

If one root of (x-2-(m+2)x+3m=0) is (3), what is the other root?

Explanation opens after your attempt
Correct Answer

A. (m)

Step 1

Concept

Putting (x=3) makes the equation true for every (m). The product is (3m) and one root is (3), so the other root is (m).

Step 2

Why this answer is correct

The correct answer is A. (m). Putting (x=3) makes the equation true for every (m). The product is (3m) and one root is (3), so the other root is (m).

Step 3

Exam Tip

(x=3) रखने पर समीकरण हर (m) के लिए सही हो जाता है। गुणनफल (3m) है और एक जड़ (3), इसलिए दूसरी जड़ (m) है।

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यदि (x-2-(m-2)x+m-6=0) की एक जड़ (3) है, तो दूसरी जड़ क्या होगी?

If one root of (x-2-(m-2)x+m-6=0) is (3), what is the other root?

Explanation opens after your attempt
Correct Answer

A. (1)

Step 1

Concept

Putting (x=3) gives (9-3(m-2)+m-6=0), so \(m=\frac{9}{2}\). The product is \(-\frac{3}{2}\), so the other root is \(-\frac{1}{2}\); hence no option is correct.

Step 2

Why this answer is correct

The correct answer is A. (1). Putting (x=3) gives (9-3(m-2)+m-6=0), so \(m=\frac{9}{2}\). The product is \(-\frac{3}{2}\), so the other root is \(-\frac{1}{2}\); hence no option is correct.

Step 3

Exam Tip

(x=3) रखने पर (9-3(m-2)+m-6=0), इसलिए \(m=\frac{9}{2}\)। गुणनफल \(m-6=-\frac{3}{2}\) है, अतः दूसरी जड़ \(-\frac{1}{2}\) होगी, इसलिए कोई विकल्प सही नहीं है।

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यदि (2x-2-(3t+1)x+t-2+t=0) की जड़ें (t) और \(\frac{t+1}{2}\) हैं, तो यह कथन किसके लिए सही है?

If the roots of (2x-2-(3t+1)x+t-2+t=0) are (t) and \(\frac{t+1}{2}\), for which values is this statement true?

Explanation opens after your attempt
Correct Answer

A. हर (t) के लिएFor every (t)

Step 1

Concept

The sum is \(\frac{3t+1}{2}\) and the product is (\frac{t(t+1)}{2}). These match \(-\frac{b}{a}\) and \(\frac{c}{a}\) for every (t).

Step 2

Why this answer is correct

The correct answer is A. हर (t) के लिए / For every (t). The sum is \(\frac{3t+1}{2}\) and the product is (\frac{t(t+1)}{2}). These match \(-\frac{b}{a}\) and \(\frac{c}{a}\) for every (t).

Step 3

Exam Tip

इन जड़ों का योग \(\frac{3t+1}{2}\) और गुणनफल (\frac{t(t+1)}{2}) है। ये दिए गए समीकरण के \(-\frac{b}{a}\) और \(\frac{c}{a}\) से हर (t) पर मेल खाते हैं।

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यदि \(x^2-2x-8=0\) की जड़ें \(\alpha,\beta\) हैं, तो (\(\alpha+3\)\(\beta+3\)) का मान क्या है?

If \(\alpha,\beta\) are the roots of \(x^2-2x-8=0\), what is (\(\alpha+3\)\(\beta+3\))?

Explanation opens after your attempt
Correct Answer

A. (7)

Step 1

Concept

We use (\(\alpha+3\)\(\beta+3\)=\alpha\beta+3\(\alpha+\beta\)+9). Since \(\alpha+\beta=2\) and \(\alpha\beta=-8\), the value is (7).

Step 2

Why this answer is correct

The correct answer is A. (7). We use (\(\alpha+3\)\(\beta+3\)=\alpha\beta+3\(\alpha+\beta\)+9). Since \(\alpha+\beta=2\) and \(\alpha\beta=-8\), the value is (7).

Step 3

Exam Tip

(\(\alpha+3\)\(\beta+3\)=\alpha\beta+3\(\alpha+\beta\)+9) है। \(\alpha+\beta=2\) और \(\alpha\beta=-8\), इसलिए मान (7) है।

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यदि \(x^2+4x+c=0\) की दोनों जड़ें वास्तविक और ऋणात्मक हैं, तो कौन-सी शर्त पर्याप्त और आवश्यक है?

If both roots of \(x^2+4x+c=0\) are real and negative, which condition is necessary and sufficient?

Explanation opens after your attempt
Correct Answer

A. \(0<c\le4\)

Step 1

Concept

The sum (-4) is already negative and the product must be positive, so (c>0). For real roots, \(16-4c\ge0\), hence \(0<c\le4\).

Step 2

Why this answer is correct

The correct answer is A. \(0<c\le4\). The sum (-4) is already negative and the product must be positive, so (c>0). For real roots, \(16-4c\ge0\), hence \(0<c\le4\).

Step 3

Exam Tip

योग (-4) पहले से ऋणात्मक है और गुणनफल धनात्मक चाहिए, इसलिए (c>0)। वास्तविक जड़ों के लिए \(16-4c\ge0\), अतः \(0<c\le4\)।

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\(x^2-2px+p^2-9=0\) की जड़ों के बारे में कौन-सा कथन सही है?

Which statement is correct about the roots of \(x^2-2px+p^2-9=0\)?

Explanation opens after your attempt
Correct Answer

A. जड़ों का अंतर हमेशा (6) हैThe difference of roots is always (6)

Step 1

Concept

The equation can be written as ((x-p)2-9=0). The roots are (p+3) and (p-3), so the difference is (6).

Step 2

Why this answer is correct

The correct answer is A. जड़ों का अंतर हमेशा (6) है / The difference of roots is always (6). The equation can be written as ((x-p)2-9=0). The roots are (p+3) and (p-3), so the difference is (6).

Step 3

Exam Tip

समीकरण को ((x-p)2-9=0) लिखा जा सकता है। जड़ें (p+3) और (p-3) हैं, इसलिए अंतर (6) है।

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यदि \(x^2-3x-1=0\) की जड़ें \(\alpha,\beta\) हैं, तो \(\alpha^2+3\beta+\alpha\beta\) का सही मान क्या है?

If \(\alpha,\beta\) are the roots of \(x^2-3x-1=0\), what is the correct value of \(\alpha^2+3\beta+\alpha\beta\)?

Explanation opens after your attempt
Correct Answer

A. (9)

Step 1

Concept

Use \(\alpha^2=3\alpha+1\) and \(\alpha\beta=-1\). Then the expression is (3\alpha+1+3\beta-1=3\(\alpha+\beta\)=9).

Step 2

Why this answer is correct

The correct answer is A. (9). Use \(\alpha^2=3\alpha+1\) and \(\alpha\beta=-1\). Then the expression is (3\alpha+1+3\beta-1=3\(\alpha+\beta\)=9).

Step 3

Exam Tip

\(\alpha^2=3\alpha+1\) और \(\alpha\beta=-1\) रखें। तब व्यंजक (3\alpha+1+3\beta-1=3\(\alpha+\beta\)=9) होगा।

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यदि \(x^2-3x-1=0\) की जड़ें \(\alpha,\beta\) हैं, तो \(\alpha^2+3\beta+\alpha\beta\) का मान क्या है जब \(\alpha\) बड़ी जड़ है?

If \(\alpha,\beta\) are the roots of \(x^2-3x-1=0\), what is \(\alpha^2+3\beta+\alpha\beta\) when \(\alpha\) is the larger root?

Explanation opens after your attempt
Correct Answer

A. (8)

Step 1

Concept

Since \(\alpha^2=3\alpha+1\), the expression becomes (3\alpha+1+3\beta-1=3\(\alpha+\beta\)=9), so no option is correct. The correct value is (9).

Step 2

Why this answer is correct

The correct answer is A. (8). Since \(\alpha^2=3\alpha+1\), the expression becomes (3\alpha+1+3\beta-1=3\(\alpha+\beta\)=9), so no option is correct. The correct value is (9).

Step 3

Exam Tip

क्योंकि \(\alpha^2=3\alpha+1\), व्यंजक (3\alpha+1+3\beta-1=3\(\alpha+\beta\)=9) बनता है, इसलिए कोई विकल्प सही नहीं है। सही मान (9) होगा।

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यदि \(x^2+ax+b=0\) की जड़ें \(2+\sqrt{3}\) और \(2-\sqrt{3}\) हैं, तो (a+b) का मान क्या है?

If the roots of \(x^2+ax+b=0\) are \(2+\sqrt{3}\) and \(2-\sqrt{3}\), what is (a+b)?

Explanation opens after your attempt
Correct Answer

A. (-3)

Step 1

Concept

The sum of roots is (4), so (a=-4). The product is (1), so (b=1), hence (a+b=-3).

Step 2

Why this answer is correct

The correct answer is A. (-3). The sum of roots is (4), so (a=-4). The product is (1), so (b=1), hence (a+b=-3).

Step 3

Exam Tip

जड़ों का योग (4) है, इसलिए (a=-4)। गुणनफल (1) है, इसलिए (b=1), अतः (a+b=-3)।

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यदि (x-2+(m-5)x+9=0) की जड़ें बराबर पर विपरीत चिह्न वाली नहीं हैं और समान हैं, तो (m) के मान क्या हैं?

If (x-2+(m-5)x+9=0) has equal roots that are not of opposite signs, what are the values of (m)?

Explanation opens after your attempt
Correct Answer

A. (11) और (-1)(11) and (-1)

Step 1

Concept

For equal roots, ((m-5)2-36=0). Thus \(m-5=\pm6\), so (m=11) or (m=-1).

Step 2

Why this answer is correct

The correct answer is A. (11) और (-1) / (11) and (-1). For equal roots, ((m-5)2-36=0). Thus \(m-5=\pm6\), so (m=11) or (m=-1).

Step 3

Exam Tip

समान जड़ों के लिए ((m-5)2-36=0) होगा। इसलिए \(m-5=\pm6\), अतः (m=11) या (m=-1)।

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यदि \(2x^2-5x+3=0\) की जड़ें \(\alpha,\beta\) हैं, तो \(\alpha^3+\beta^3\) का मान क्या है?

If \(\alpha,\beta\) are the roots of \(2x^2-5x+3=0\), what is \(\alpha^3+\beta^3\)?

Explanation opens after your attempt
Correct Answer

A. \(\frac{35}{8}\)

Step 1

Concept

Here \(\alpha+\beta=\frac{5}{2}\) and \(\alpha\beta=\frac{3}{2}\). Using (\alpha-3+\beta-3=\(\alpha+\beta\)3-3\alpha\beta\(\alpha+\beta\)), we get \(\frac{35}{8}\).

Step 2

Why this answer is correct

The correct answer is A. \(\frac{35}{8}\). Here \(\alpha+\beta=\frac{5}{2}\) and \(\alpha\beta=\frac{3}{2}\). Using (\alpha-3+\beta-3=\(\alpha+\beta\)3-3\alpha\beta\(\alpha+\beta\)), we get \(\frac{35}{8}\).

Step 3

Exam Tip

यहाँ \(\alpha+\beta=\frac{5}{2}\) और \(\alpha\beta=\frac{3}{2}\) है। (\alpha-3+\beta-3=\(\alpha+\beta\)3-3\alpha\beta\(\alpha+\beta\)) से \(\frac{35}{8}\) मिलता है।

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यदि \(x^2-7x+10=0\) की जड़ें \(\alpha,\beta\) हैं, तो \(\frac{\alpha+2}{\alpha-2}+\frac{\beta+2}{\beta-2}\) का मान क्या है?

If \(\alpha,\beta\) are the roots of \(x^2-7x+10=0\), what is \(\frac{\alpha+2}{\alpha-2}+\frac{\beta+2}{\beta-2}\)?

Explanation opens after your attempt
Correct Answer

A. अपरिभाषितUndefined

Step 1

Concept

One root can be \(\alpha=2\), which makes \(\alpha-2=0\). Therefore the expression is undefined; always check zero denominators first in exams.

Step 2

Why this answer is correct

The correct answer is A. अपरिभाषित / Undefined. One root can be \(\alpha=2\), which makes \(\alpha-2=0\). Therefore the expression is undefined; always check zero denominators first in exams.

Step 3

Exam Tip

जड़ों में से एक \(\alpha=2\) हो सकती है, जिससे \(\alpha-2=0\) बनता है। इसलिए व्यंजक अपरिभाषित है; परीक्षा में हर पहले शून्य हर देखें।

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यदि \(x^2-8x+15=0\) की जड़ें \(\alpha,\beta\) हैं, तो \(\frac{\alpha+2}{\alpha-2}+\frac{\beta+2}{\beta-2}\) का मान क्या है?

If \(\alpha,\beta\) are the roots of \(x^2-8x+15=0\), what is \(\frac{\alpha+2}{\alpha-2}+\frac{\beta+2}{\beta-2}\)?

Explanation opens after your attempt
Correct Answer

A. (8)

Step 1

Concept

The roots are (3) and (5). Substitution gives \(\frac{5}{1}+\frac{7}{3}=\frac{22}{3}\), so none of the options is correct; the correct value should be \(\frac{22}{3}\).

Step 2

Why this answer is correct

The correct answer is A. (8). The roots are (3) and (5). Substitution gives \(\frac{5}{1}+\frac{7}{3}=\frac{22}{3}\), so none of the options is correct; the correct value should be \(\frac{22}{3}\).

Step 3

Exam Tip

जड़ें (3) और (5) हैं। सीधे रखने पर \(\frac{5}{1}+\frac{7}{3}=\frac{22}{3}\) आता है, इसलिए विकल्पों में कोई सही नहीं; सही प्रश्न के लिए उत्तर \(\frac{22}{3}\) होना चाहिए।

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(4x-2-4(a-1)x+a-2-4a=0) की जड़ें वास्तविक हों, तो (a) पर सही शर्त क्या है?

For (4x-2-4(a-1)x+a-2-4a=0) to have real roots, what is the correct condition on (a)?

Explanation opens after your attempt
Correct Answer

A. \(a\le1\)

Step 1

Concept

For real roots, \(D\ge0\) is required. Here (D=16(1-a)), so \(a\le1\).

Step 2

Why this answer is correct

The correct answer is A. \(a\le1\). For real roots, \(D\ge0\) is required. Here (D=16(1-a)), so \(a\le1\).

Step 3

Exam Tip

वास्तविक जड़ों के लिए \(D\ge0\) चाहिए। यहाँ (D=16(1-a)), इसलिए \(a\le1\) है।

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यदि \(x^2+px+12=0\) की जड़ें (r) और (r+1) हैं, तो (p) के संभव मान क्या हैं?

If the roots of \(x^2+px+12=0\) are (r) and (r+1), what are the possible values of (p)?

Explanation opens after your attempt
Correct Answer

A. (7) और (-7)(7) and (-7)

Step 1

Concept

From (r(r+1)=12), we get (r=3) or (r=-4). The sum is (7) or (-7), so (p=-7) or (p=7).

Step 2

Why this answer is correct

The correct answer is A. (7) और (-7) / (7) and (-7). From (r(r+1)=12), we get (r=3) or (r=-4). The sum is (7) or (-7), so (p=-7) or (p=7).

Step 3

Exam Tip

(r(r+1)=12) से (r=3) या (r=-4) मिलता है। जड़ों का योग (7) या (-7) है, इसलिए (p=-7) या (p=7)।

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यदि \(kx^2-8x+k=0\) की जड़ें वास्तविक और व्युत्क्रम हैं, तो (k) पर सही शर्त क्या है?

If the roots of \(kx^2-8x+k=0\) are real and reciprocal, what is the correct condition on (k)?

Explanation opens after your attempt
Correct Answer

A. \(k\neq0\) और \(k^2\le16\)\(k\neq0\) and \(k^2\le16\)

Step 1

Concept

For reciprocal roots, \(\frac{k}{k}=1\), so \(k\neq0\) is needed. For real roots, \(64-4k^2\ge0\), hence \(k^2\le16\).

Step 2

Why this answer is correct

The correct answer is A. \(k\neq0\) और \(k^2\le16\) / \(k\neq0\) and \(k^2\le16\). For reciprocal roots, \(\frac{k}{k}=1\), so \(k\neq0\) is needed. For real roots, \(64-4k^2\ge0\), hence \(k^2\le16\).

Step 3

Exam Tip

व्युत्क्रम जड़ों के लिए \(\frac{k}{k}=1\) है, इसलिए \(k\neq0\) चाहिए। वास्तविक जड़ों के लिए \(64-4k^2\ge0\), अतः \(k^2\le16\)।

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यदि \(x^2-5x+2=0\) की जड़ें \(\alpha,\beta\) हैं, तो \(\frac{1}{\alpha^2}+\frac{1}{\beta^2}\) का मान क्या है?

If \(\alpha,\beta\) are the roots of \(x^2-5x+2=0\), what is \(\frac{1}{\alpha^2}+\frac{1}{\beta^2}\)?

Explanation opens after your attempt
Correct Answer

A. \(\frac{21}{4}\)

Step 1

Concept

We use (\frac{1}{\alpha-2}+\frac{1}{\beta-2}=\frac{\alpha-2+\beta-2}{\(\alpha\beta\)2}). Since \(\alpha^2+\beta^2=21\) and (\(\alpha\beta\)2=4), the value is \(\frac{21}{4}\).

Step 2

Why this answer is correct

The correct answer is A. \(\frac{21}{4}\). We use (\frac{1}{\alpha-2}+\frac{1}{\beta-2}=\frac{\alpha-2+\beta-2}{\(\alpha\beta\)2}). Since \(\alpha^2+\beta^2=21\) and (\(\alpha\beta\)2=4), the value is \(\frac{21}{4}\).

Step 3

Exam Tip

(\frac{1}{\alpha-2}+\frac{1}{\beta-2}=\frac{\alpha-2+\beta-2}{\(\alpha\beta\)2}) होता है। \(\alpha^2+\beta^2=21\) और (\(\alpha\beta\)2=4), इसलिए मान \(\frac{21}{4}\) है।

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(x-2-(a+4)x+4a=0) के लिए कौन-सा कथन हमेशा सत्य है?

Which statement is always true for (x-2-(a+4)x+4a=0)?

Explanation opens after your attempt
Correct Answer

A. (4) हमेशा एक जड़ है(4) is always a root

Step 1

Concept

Putting (x=4) gives (16-4(a+4)+4a=0). Hence (4) is always one root and the other root is (a).

Step 2

Why this answer is correct

The correct answer is A. (4) हमेशा एक जड़ है / (4) is always a root. Putting (x=4) gives (16-4(a+4)+4a=0). Hence (4) is always one root and the other root is (a).

Step 3

Exam Tip

(x=4) रखने पर (16-4(a+4)+4a=0) मिलता है। अतः (4) हमेशा एक जड़ है और दूसरी जड़ (a) होती है।

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यदि \(2x^2+mx+8=0\) की जड़ें (1:2) के अनुपात में हैं, तो (m) के संभव मान क्या हैं?

If the roots of \(2x^2+mx+8=0\) are in the ratio (1:2), what are the possible values of (m)?

Explanation opens after your attempt
Correct Answer

A. \(6\sqrt{2}\) और \(-6\sqrt{2}\)\(6\sqrt{2}\) and \(-6\sqrt{2}\)

Step 1

Concept

Let the roots be (r) and (2r), then \(2r^2=4\) gives \(r=\pm\sqrt{2}\). Since \(3r=-\frac{m}{2}\), we get \(m=\pm6\sqrt{2}\).

Step 2

Why this answer is correct

The correct answer is A. \(6\sqrt{2}\) और \(-6\sqrt{2}\) / \(6\sqrt{2}\) and \(-6\sqrt{2}\). Let the roots be (r) and (2r), then \(2r^2=4\) gives \(r=\pm\sqrt{2}\). Since \(3r=-\frac{m}{2}\), we get \(m=\pm6\sqrt{2}\).

Step 3

Exam Tip

जड़ें (r) और (2r) मानें, तब \(2r^2=4\) से \(r=\pm\sqrt{2}\) मिलता है। योग \(3r=-\frac{m}{2}\), इसलिए \(m=\pm6\sqrt{2}\)।

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यदि \(x^2-6x+5=0\) की जड़ें \(\alpha,\beta\) हैं, तो \(3\alpha-2\) और \(3\beta-2\) जड़ों वाला समीकरण कौन-सा है?

If \(\alpha,\beta\) are the roots of \(x^2-6x+5=0\), which equation has roots \(3\alpha-2\) and \(3\beta-2\)?

Explanation opens after your attempt
Correct Answer

A. \(x^2-14x+13=0\)

Step 1

Concept

The original roots are (1) and (5), so the new roots are (1) and (13). Their equation is \(x^2-14x+13=0\).

Step 2

Why this answer is correct

The correct answer is A. \(x^2-14x+13=0\). The original roots are (1) and (5), so the new roots are (1) and (13). Their equation is \(x^2-14x+13=0\).

Step 3

Exam Tip

मूल जड़ें (1) और (5) हैं, इसलिए नई जड़ें (1) और (13) हैं। उनका समीकरण \(x^2-14x+13=0\) है।

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यदि (x-2-2(k+2)x+k-2+5=0) की जड़ें समान हैं, तो (k) का मान क्या होगा?

If (x-2-2(k+2)x+k-2+5=0) has equal roots, what is the value of (k)?

Explanation opens after your attempt
Correct Answer

A. \(\frac{1}{4}\)

Step 1

Concept

For equal roots, put (D=0). Simplifying (4(k+2)2-4\(k^2+5\)=0) gives (4k-1=0), so \(k=\frac{1}{4}\).

Step 2

Why this answer is correct

The correct answer is A. \(\frac{1}{4}\). For equal roots, put (D=0). Simplifying (4(k+2)2-4\(k^2+5\)=0) gives (4k-1=0), so \(k=\frac{1}{4}\).

Step 3

Exam Tip

समान जड़ों के लिए (D=0) रखें। (4(k+2)2-4\(k^2+5\)=0) से (4k+3=0) नहीं, बल्कि (4k-1=0) नहीं; सही सरलीकरण (4k-1=0) देता है, इसलिए \(k=\frac{1}{4}\)।

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यदि \(3x^2-11x+p=0\) की जड़ों का अंतर \(\frac{5}{3}\) है, तो (p) का मान क्या है?

If the difference between the roots of \(3x^2-11x+p=0\) is \(\frac{5}{3}\), what is the value of (p)?

Explanation opens after your attempt
Correct Answer

A. (8)

Step 1

Concept

Here \(\alpha+\beta=\frac{11}{3}\) and (\(\alpha-\beta\)2=\frac{25}{9}). Using (\(\alpha-\beta\)2=\(\alpha+\beta\)2-4\alpha\beta), we get \(\alpha\beta=\frac{8}{3}\), so (p=8).

Step 2

Why this answer is correct

The correct answer is A. (8). Here \(\alpha+\beta=\frac{11}{3}\) and (\(\alpha-\beta\)2=\frac{25}{9}). Using (\(\alpha-\beta\)2=\(\alpha+\beta\)2-4\alpha\beta), we get \(\alpha\beta=\frac{8}{3}\), so (p=8).

Step 3

Exam Tip

यहाँ \(\alpha+\beta=\frac{11}{3}\) और (\(\alpha-\beta\)2=\frac{25}{9}) है। सूत्र (\(\alpha-\beta\)2=\(\alpha+\beta\)2-4\alpha\beta) से \(\alpha\beta=\frac{8}{3}\), इसलिए (p=8)।

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