题目内容
【题目】(1)计算:(-8xy2)(-x)3+(-2x4)4+2x10(-2x2)3
(2)先化简,再求值:(y+2)(y2-2y+1)-y(y2+1),其中y=
【答案】(1)x4y2;(2)-4y+2,原式=0.
【解析】
(1)先算乘方,再算乘法,最后算加减;
(2)先算乘法,再合并同类项,最后代入求出即可.
解:(1)(-8xy2)(-x)3+(-2x4)4+2x10(-2x2)3
=(-8xy2)(-x3)+16x16+2x10(-8x6)
=x4y2+16x16-16x16
=x4y2;
(2)(y+2)(y2-2y+1)-y(y2+1)
=y3-2y2+y+2y2-4y+2-y3-y
=-4y+2,
当y=时,原式=-2+2=0.
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