0.3分之(1.7-2x)=0.7分之(x)-1 (1.7-2x)/0.3 =x/0.7 -1 10(1.7-2x)/3 =10x/7 -1 70(1.7-2x)=30x-21 119-140x=30x-21 119+21=170x 140=170x x=14/17