2xy 2与x的取值无关求y的值 2xy-y的值是多少?
2xy-y的值是多少?解:1/x -1/y2等式左边通分,得(y-x)/(xy)2等式两边同乘以-xy,得x-y-2xy(2x 3xy-2y)/(x-2xy-y