2/5(3x +1)-5/7(x-1)=x-3
2/5*(3*x+1)-5/7*(x-1) = x-3 2/5*3*x+2/5*1-5/7*x+5/7*1 = x-3 9/35 + 17*x/35 = x-3 17*x/35 = -144/35 + x -18*x/35 = -144/35 x = -144/35 / (-18/35) х=8