若xy/x+y=2,则3x-xy+3y/-x+3xy-y=
问题描述:
若xy/x+y=2,则3x-xy+3y/-x+3xy-y=
答
原题是 xy/(x+y)=2 求(3x-xy+3y)/(-x+3xy-y)吗 如果是 那么计算如下由xy/(x+y)=2 得x+y=xy/2(3x-xy+3y)/(-x+3xy-y=[3(x+y)-xy]/[-(x+y)+3xy]=[3xy/2-xy]/[-xy/2+3xy]=(xy/2)/(5xy/2)=xy/2×2/5x...