\(9x^2+kx+25\) पूर्ण वर्ग हो और (k) ऋणात्मक हो तो (k) क्या है?
If \(9x^2+kx+25\) is a perfect square and (k) is negative, what is (k)?
Explanation opens after your attempt
B. (-30)correct middle
Concept
(9x-2=(3x)2), \(25=5^2\), so the middle term is \(-2\cdot3x\cdot5=-30x\). In exams follow the given sign.
Why this answer is correct
The correct answer is B. (-30) / correct middle. (9x-2=(3x)2), \(25=5^2\), so the middle term is \(-2\cdot3x\cdot5=-30x\). In exams follow the given sign.
Exam Tip
(9x-2=(3x)2), \(25=5^2\), इसलिए मध्य पद \(-2\cdot3x\cdot5=-30x\) है। परीक्षा में दिए गए चिन्ह का पालन करें।
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