问题 解答题
2x-y
+|y+2|=0
,求代数式[(x-y)2+(x+y)(x-y)]÷2x的值.
答案

2x-y
+|y+2|=0,

∴y+2=0,2x-y=0,

解得x=-1,y=-2;

∴[(x-y)2+(x+y)(x-y)]÷2x,

=[(x-y)(x-y+x+y)]÷2x,

=[(x-y)×2x]÷2x,

=x-y,

当x=-1,y=-2时,

原式=x-y,

=-1+2,

=1.

填空题
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