先化简,后求值:3x2y-[2xy2-2(xy-1.5x2y)+xy]+3xy2,其中|x+2|+(y-12)2=0.-数学

题目简介

先化简,后求值:3x2y-[2xy2-2(xy-1.5x2y)+xy]+3xy2,其中|x+2|+(y-12)2=0.-数学

题目详情

先化简,后求值:3x2y-[2xy2-2(xy-1.5x2y)+xy]+3xy2,其中|x+2|+(y-
1
2
)2=0
题型:解答题难度:中档来源:不详

答案

原式=3x2y-2xy2+2xy-3x2y-xy+3xy2
=xy2+xy,
∵|x+2|+(y-class="stub"1
2
)2=0,∴x=-2,y=class="stub"1
2

则原式=-2×class="stub"1
4
-2×class="stub"1
2

=-class="stub"1
2
-1
=-1class="stub"1
2

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