Question

[3x的平方-(x+y)(y-x)][2(-x-y)(y-x)+2x的平方+3y的平方],x=-二分之一,y=1.5

Answer 1

[3x的平方-(x+y)(y-x)][2(-x-y)(y-x)+2x的平方+3y的平方

=[3x²+(x+y)(x-y)][(x+y)(x-y)+2x²+3y²]

=[3x²+(x²-y²)][x²-y²)+2x²+3y²]

=[4x²-y²][3x²+2y²]

x=-1/2 y=3/2

=(4 * 1/4 - 9/4)(3* 1/4 + 2*9/4)

=-5/4 * 21/4

=-105/16