三个分式通分题（1）：2xy/(x+y)²与x/x²-y²（2）：x-y/2x+2y与xy/(x+y)²（3）：2mn/4m²-4与2m-3/2m+3
问题描述：
三个分式通分题
（1）：2xy/(x+y)²与x/x²-y²
（2）：x-y/2x+2y与xy/(x+y)²
（3）：2mn/4m²-4与2m-3/2m+3
答
2xy(x-y)/[(x+y)²(x-y)]与x(x+y)/[(x+y)²(x-y)]
(x²-y²)/2(x+y)²与2xy/2(x+y)²
2mn(2m+3)/[4(m²-1)(2m+3)]与(2m-3)(4m²-4)/[4(m²-1)(2m+3)]
答
（1）2xy(x-y)/[(x+y)²(x-y)]与x(x+y)/[(x+y)²(x-y)](2) (x²-y²)/2(x+y)²与2xy/2(x+y)²(3)2mn(2m+3)/[4(m²-1)(2m+3)]与(2m-3)(4m²-4)/[4(m²-1)(2m+3)]