(x+x+2.5)*(3/5)=75-(3/7)x

问题描述:

(x+x+2.5)*(3/5)=75-(3/7)x

2x+2.5=[75-(3/7)x]*(5/3)=125-(5/7)x
(2+5/7)x=(19/7)x=125-2.5=245/2
x=(245/2)*(7/19)=1715/38