计算:(x-1-y-1)÷(x-2-y-2)-xy(x+y)-1.-数学

题目简介

计算:(x-1-y-1)÷(x-2-y-2)-xy(x+y)-1.-数学

题目详情

计算:(x-1-y-1)÷(x-2-y-2)-xy(x+y)-1
题型:解答题难度:中档来源:不详

答案

原式=(class="stub"1
x
-class="stub"1
y
)÷(class="stub"1
x2
-class="stub"1
y2
)-class="stub"xy
x+y

=class="stub"y-x
xy
÷
(y-x)(y+x)
x2y2
-class="stub"xy
x+y

=class="stub"y-x
xy
×
x2y2
(y-x)(y+x)
-class="stub"xy
x+y

=class="stub"xy
y+x
-class="stub"xy
x+y

=0.

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