题目内容
已知:
,求2(xy2+x2y)﹣[2xy2﹣3(1﹣x2y)]﹣2的值.
解:原式=2xy2+2x2y﹣[2xy2﹣3+x2y]﹣2=2xy2+2x2y﹣2xy2+3﹣3x2y﹣2
=(2﹣2)xy2+(2﹣3)x2y+(3﹣2)=﹣x2y+1;
∵(x+2)2≧0,
,
又∵
∴x=﹣2,
∴原式=﹣
=﹣1.
=(2﹣2)xy2+(2﹣3)x2y+(3﹣2)=﹣x2y+1;
∵(x+2)2≧0,
又∵
∴x=﹣2,
∴原式=﹣
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