先化简再求值:5xy2-[2x2y-(2x2y-xy2)]-4xy2-x,其中,x=-12,y=1623.-数学

题目简介

先化简再求值:5xy2-[2x2y-(2x2y-xy2)]-4xy2-x,其中,x=-12,y=1623.-数学

题目详情

先化简再求值:5xy2-[2x2y-(2x2y-xy2)]-4xy2-x,其中,x=-
1
2
,y=16
2
3
题型:解答题难度:中档来源:不详

答案

5xy2-[2x2y-(2x2y-xy2)]-4xy2-x
=5xy2-[2x2y-2x2y+xy2]-4xy2-x
=5xy2-xy2-4xy2-x
=-x
x=-class="stub"1
2
,y=16class="stub"2
3
时,原式=-(-class="stub"1
2
)=class="stub"1
2

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