(x-78):(5x/7+78)=3:

问题描述:

(x-78):(5x/7+78)=3:

(x-78):(5x/7+78)=3:4
4*(x-78)=3*(5x/7+78)
4x-4*78=15x/7+3*78
13x/7=7*78
x/7=7*6
x=7*42
x=294