Concept-wise Practice

conjugate roots MCQ Questions for Class 10

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

Practice Questions

8 questions tagged with conjugate roots.

Question 1/8 Expert Mathematics Chapter 2: Polynomials Irrational numbers and real numbers Class 10 Level 27

यदि \(5+\sqrt{21}\) किसी परिमेय गुणांक वाले द्विघात बहुपद का शून्यक है, तो उस बहुपद का एक संभव रूप कौन सा है?

If \(5+\sqrt{21}\) is a zero of a quadratic polynomial with rational coefficients, which is one possible form of that polynomial?

Explanation opens after your attempt
Correct Answer

A. \(x^2-10x+4\)

Step 1

Concept

The other zero will be \(5-\sqrt{21}\). Sum (10) and product (25-21=4) give the polynomial \(x^2-10x+4\).

Step 2

Why this answer is correct

The correct answer is A. \(x^2-10x+4\). The other zero will be \(5-\sqrt{21}\). Sum (10) and product (25-21=4) give the polynomial \(x^2-10x+4\).

Step 3

Exam Tip

दूसरा शून्यक \(5-\sqrt{21}\) होगा। योग (10) और गुणनफल (25-21=4) से बहुपद \(x^2-10x+4\) बनता है।

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Question 2/8 Expert Mathematics Chapter 2: Polynomials Irrational numbers and real numbers Class 10 Level 27

यदि (p(x)=x-2-2kx+20) के शून्यक \(k+\sqrt{5}\) और \(k-\sqrt{5}\) हैं, तो (k) का धनात्मक मान क्या है?

If the zeroes of (p(x)=x-2-2kx+20) are \(k+\sqrt{5}\) and \(k-\sqrt{5}\), what is the positive value of (k)?

Explanation opens after your attempt
Correct Answer

A. (5)

Step 1

Concept

From the product \(k^2-5=20\) we get \(k^2=25\) and positive (k=5). In exams find the unknown from the product.

Step 2

Why this answer is correct

The correct answer is A. (5). From the product \(k^2-5=20\) we get \(k^2=25\) and positive (k=5). In exams find the unknown from the product.

Step 3

Exam Tip

गुणनफल \(k^2-5=20\) से \(k^2=25\) और धनात्मक (k=5) है। परीक्षा में गुणनफल से अज्ञात निकालें।

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Question 3/8 Expert Mathematics Chapter 2: Polynomials Irrational numbers and real numbers Class 10 Level 26

यदि (p(x)=x-2-6x+k) के शून्यक \(3+\sqrt{2}\) और \(3-\sqrt{2}\) हैं, तो (k) का मान क्या है?

If the zeroes of (p(x)=x-2-6x+k) are \(3+\sqrt{2}\) and \(3-\sqrt{2}\), what is the value of (k)?

Explanation opens after your attempt
Correct Answer

A. (7)

Step 1

Concept

The product (\(3+\sqrt{2}\)\(3-\sqrt{2}\)=9-2=7), so (k=7). In exams connect the constant term with the product of zeroes.

Step 2

Why this answer is correct

The correct answer is A. (7). The product (\(3+\sqrt{2}\)\(3-\sqrt{2}\)=9-2=7), so (k=7). In exams connect the constant term with the product of zeroes.

Step 3

Exam Tip

गुणनफल (\(3+\sqrt{2}\)\(3-\sqrt{2}\)=9-2=7) है, इसलिए (k=7) होगा। परीक्षा में स्थिर पद को शून्यकों के गुणनफल से जोड़ें।

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Question 4/8 Expert Mathematics Chapter 2: Polynomials Irrational numbers and real numbers Class 10 Level 26

यदि (p(x)=x-2-2kx+9) के शून्यक \(k+\sqrt{7}\) और \(k-\sqrt{7}\) हैं, तो (k) का मान क्या होगा?

If the zeroes of (p(x)=x-2-2kx+9) are \(k+\sqrt{7}\) and \(k-\sqrt{7}\), what is the value of (k)?

Explanation opens after your attempt
Correct Answer

A. (4)

Step 1

Concept

From the product \(k^2-7=9\), we get \(k^2=16\), and (k=4) fits the given form. In exams use the product to find the unknown.

Step 2

Why this answer is correct

The correct answer is A. (4). From the product \(k^2-7=9\), we get \(k^2=16\), and (k=4) fits the given form. In exams use the product to find the unknown.

Step 3

Exam Tip

गुणनफल \(k^2-7=9\) से \(k^2=16\) मिलता है और दिए रूप में (k=4) उपयुक्त है। परीक्षा में गुणनफल से अज्ञात निकालें।

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Question 5/8 Expert Mathematics Chapter 2: Polynomials Irrational numbers and real numbers Class 10 Level 26

यदि (p(x)) परिमेय गुणांकों वाला द्विघात बहुपद है और उसका एक शून्यक \(2+\sqrt{7}\) है, तो दूसरा शून्यक कौन सा होगा?

If (p(x)) is a quadratic polynomial with rational coefficients and one zero is \(2+\sqrt{7}\), what will be the other zero?

Explanation opens after your attempt
Correct Answer

A. \(2-\sqrt{7}\)

Step 1

Concept

With rational coefficients, \(a+\sqrt{b}\) is accompanied by \(a-\sqrt{b}\). In exams identify conjugate zeroes quickly.

Step 2

Why this answer is correct

The correct answer is A. \(2-\sqrt{7}\). With rational coefficients, \(a+\sqrt{b}\) is accompanied by \(a-\sqrt{b}\). In exams identify conjugate zeroes quickly.

Step 3

Exam Tip

परिमेय गुणांकों में \(a+\sqrt{b}\) के साथ \(a-\sqrt{b}\) भी शून्यक आता है। परीक्षा में संयुग्मी शून्यकों को तुरंत पहचानें।

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Question 6/8 Hard Mathematics Chapter 2: Polynomials Irrational numbers and real numbers Class 10 Level 28

परिमेय गुणांकों वाले किसी द्विघात बहुपद का एक शून्यक \(3-\sqrt{5}\) है। दूसरा शून्यक कौन सा होगा?

One zero of a quadratic polynomial with rational coefficients is \(3-\sqrt{5}\). What will be the other zero?

Explanation opens after your attempt
Correct Answer

A. \(3+\sqrt{5}\)

Step 1

Concept

For rational coefficients, irrational zeroes usually occur in conjugate pairs. Hence the companion zero of \(3-\sqrt{5}\) is \(3+\sqrt{5}\).

Step 2

Why this answer is correct

The correct answer is A. \(3+\sqrt{5}\). For rational coefficients, irrational zeroes usually occur in conjugate pairs. Hence the companion zero of \(3-\sqrt{5}\) is \(3+\sqrt{5}\).

Step 3

Exam Tip

परिमेय गुणांकों में अपरिमेय शून्यक सामान्यतः संयुग्मी रूप में आते हैं। इसलिए \(3-\sqrt{5}\) का साथी शून्यक \(3+\sqrt{5}\) होगा।

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Question 7/8 Hard Mathematics Chapter 2: Polynomials Irrational numbers and real numbers Class 10 Level 26

निम्न में से कौन सा बहुपद परिमेय गुणांकों वाला है और जिसके शून्यक \(1+\sqrt{2}\) तथा \(1-\sqrt{2}\) हैं?

Which polynomial has rational coefficients and zeroes \(1+\sqrt{2}\) and \(1-\sqrt{2}\)?

Explanation opens after your attempt
Correct Answer

A. \(x^2-2x-1\)

Step 1

Concept

The sum is (2) and the product is (1-2=-1), so the polynomial is \(x^2-2x-1\). Keep signs correct in exams.

Step 2

Why this answer is correct

The correct answer is A. \(x^2-2x-1\). The sum is (2) and the product is (1-2=-1), so the polynomial is \(x^2-2x-1\). Keep signs correct in exams.

Step 3

Exam Tip

योग (2) और गुणनफल (1-2=-1), इसलिए बहुपद \(x^2-2x-1\) है। परीक्षा में चिन्हों को ठीक रखें।

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Question 8/8 Hard Mathematics Chapter 2: Polynomials Irrational numbers and real numbers Class 10 Level 28

यदि \(2+\sqrt{3}\) एक बहुपद \(x^2-4x+1\) का शून्यक है, तो दूसरा शून्यक क्या होगा?

If \(2+\sqrt{3}\) is a zero of the polynomial \(x^2-4x+1\), what is the other zero?

Explanation opens after your attempt
Correct Answer

A. \(2-\sqrt{3}\)

Step 1

Concept

For a quadratic with rational coefficients, if \(a+\sqrt{b}\) is a zero then \(a-\sqrt{b}\) is also a zero. The conjugate-root rule is useful in exams.

Step 2

Why this answer is correct

The correct answer is A. \(2-\sqrt{3}\). For a quadratic with rational coefficients, if \(a+\sqrt{b}\) is a zero then \(a-\sqrt{b}\) is also a zero. The conjugate-root rule is useful in exams.

Step 3

Exam Tip

परिमेय गुणांकों वाले द्विघात में \(a+\sqrt{b}\) के साथ \(a-\sqrt{b}\) भी शून्यक होता है। परीक्षा में संयुग्मी मूल का नियम उपयोगी है।

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