已知1/x-1/y=2,求2x+5xy−2yx−2xy−y=_.
问题描述:
已知
-1 x
=2,求1 y
=______. 2x+5xy−2y x−2xy−y
答
∵
-1 x
=-1 y
=2,即x-y=-2xy,x−y xy
∴原式=
=2(x−y)+5xy x−y−2xy
=-−2xy+5xy −2xy−2xy
.3 4
故答案为:-
3 4