问题 解答题
1
x
-
1
y
=3
,求
2x+3xy-2y
x+2xy-y
的值=______.
答案

1
x
-
1
y
=3,∴x-y=-3xy,再把它整体代入原式:
2x+3xy-2y
x+2xy-y
=
2(x-y)+3xy
(x-y)+2xy
=
-6xy+3xy
-3xy+2xy
=
-3xy
-xy
=3.

故答案为3.

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