通分①x/3y与3x/2y²②x-y/2x+2y与(x-y)/(x+y)²③2mn/4m²-9与2m/2m+3
问题描述:
通分①x/3y与3x/2y²②x-y/2x+2y与(x-y)/(x+y)²③2mn/4m²-9与2m/2m+3
答
①x/(3y)=2xy/(6y²)3x/(2y²)=9x/(6y²)②(x-y)/(2x+2y)=(x²-y²)/[2(x+y)²](x-y)/(x+y)²=2(x-y)/[2(x+y)²]③2mn/(4m²-9)2m/(2m+3)=2m(2m-3)/(4m²-9)...