If 2x2 + y2 + 6x - 2xy + 9 = 0, then the value of (4x3 - y3 + x2 y2) is:
Show answer & explanation
Correct answer: A
Explanation
Correct Answer is option 1 i.e. 0
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Concept |
Understanding |
Application |
Fair calculation |
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(x2 + y2 - 2xy) = (x – y)2 |
Given 2x2 + y2 + 6x - 2xy + 9 = 0
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2x2 + y2 + 6x – 2xy + 9 = 0 x2 + x2 + y2 + 6x – 2xy + 9 = 0 (x2 + y2 - 2xy) + (x2 + 6x + 9) = 0 (x – y)2 + (x + 3)2 = 0 So, x + 3 = 0 and x – y = 0 So, x = -3 and x = y = -3 Now, (4x3 – y3 + x2y2) = 4(-3)3 – (-3)3 + (-3)2(-3)2 = 0 |
4(-3)3 – (-3)3 + (-3)2(-3)2 = - 108 + 27 + 81 = 0 |