若2x−y+|y+2|=0,求代数式[(x-y)2+(x+y)(x-y)]÷2x的值.
问题描述:
若
+|y+2|=0,求代数式[(x-y)2+(x+y)(x-y)]÷2x的值.
2x−y
答
∵
+|y+2|=0,
2x−y
∴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.