已知x分之1 减y分之1等于3 求 x-xy-y 分之 5x-xy-5y等于多少急啊
问题描述:
已知x分之1 减y分之1等于3 求 x-xy-y 分之 5x-xy-5y等于多少急啊
答
1/x-1/y=3 y-x=3xy x-y=-3xy(5x-xy-5y)/(x-xy-y) =(-15xy-xy)/(-3xy-xy) =4
已知x分之1 减y分之1等于3 求 x-xy-y 分之 5x-xy-5y等于多少急啊
1/x-1/y=3 y-x=3xy x-y=-3xy(5x-xy-5y)/(x-xy-y) =(-15xy-xy)/(-3xy-xy) =4