已知2x-y=10,求代数式[(x2+y2)-(x-y)2+2y(x-y)]÷4y的值.-数学

题目简介

已知2x-y=10,求代数式[(x2+y2)-(x-y)2+2y(x-y)]÷4y的值.-数学

题目详情

已知2x-y=10,求代数式[(x2+y2)-(x-y)2+2y(x-y)]÷4y的值.
题型:解答题难度:中档来源:不详

答案

[(x2+y2)-(x-y)2+2y(x-y)]÷4y,
=[x2+y2-x2+2xy-y2+2xy-2y2]÷4y,
=[4xy-2y2]÷4y,
=class="stub"1
2
(2x-y),
∵2x-y=10,
∴原式=class="stub"1
2
×10=5.

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