Question

化简3(x-y)^-1/2(x+y)+3/4(x-y)^+3/2(x+y) 其中x-y=2 x+7=-3

Answer 1

题目应是：3(x-y)^2-1/2(x+y)+3/4(x-y)^2+3/2(x+y) 其中x-y=2 x+y=-3
3(x-y)^2-1/2(x+y)+3/4(x-y)^2+3/2(x+y)
=15/4(x-y)^2+(x+y)
=15/4*2^2+(-3)
=15-3
=12

Answer 2

(1)
3(x-y)^-1/2(x+y)+3/4(x-y)^+3/2(x+y)
=15/4(x-y)^+x+y
（2）因为x-y=2 x+7=-3所以得x=4 y=2代入原式得 原式=21