If x4 + 2x3 + ax2 + bx + 9 is a perfect square, where a and b are positive real numbers, then the value of a and b are
Show answer & explanation
Correct answer: C
Explanation
The correct answer is Option 3 i.e. a = 7, b = 6
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(a + b + c)2 = a2 + b2 + c2 + 2ab + 2bc + 2ca (x2 + x + 3)2 = x4 + x2 + 9 + 2x3 + 6x + 6x2 = x4 + 2x3 + 7x2 + 6x + 9 On comparing with x4 + 2x3 + ax2 + bx + 9 a = 7, b = 6 |