先化简,后求值[(x-y)3(3次方)+(x2-y2)(x-y)]/(-2x),其中x=3,y=-2_其他解答

先化简,后求值[(x-y)3(3次方)+(x2-y2)(x-y)]/(-2x),其中x=3,y=-2

人气：246 ℃　时间：2020-04-04 11:38:09

解答

[(x-y)3(3次方)+(x2-y2)(x-y)]/(-2x)
=(x-y)^2[(x-y)+(x+y)]/(-2x)
=(x-y)^2[2x]/(-2x)
=-(x-y)^2
=-(3+2)^2=-25