Q421
If 2x2 + y2 + 6x - 2xy + 9 = 0, then the value of (4x3 - y3 + x2y2) is:
A.
0
AnswerB.
9
C.
-3
D.
-9
Answer: Option A
Solution
Answer: Option A
Solution:
2x2 + y2 + 6x - 2xy + 9 = 0x2 + x2 + y2 + 6x - 2xy + 9= 0
(x2 + y2 - 2xy) + (x2 + 6x + 9) = 0
(x - y)2 + (x + 3)2 = 0
x = y, x = -3
4x3 - y3 + x2y2
= 4x3 - x3 + x4
= 3x3 + x4
= -x4 + x4
= 0