(0.5X-3)/0.04-x=[0.4(0.5x-3)]/0.5

(0.5X-3)/0.04-x=[0.4(0.5x-3)]/0.5
(0.5X-3)/0.04-x=[0.4(0.5x-3)]/0.5

(0.5X-3)/0.04-x=[0.4(0.5x-3)]/0.5
(0.5X-3)/0.04-x=[0.4(0.5x-3)]/0.5
(0.5X-3)/(1/25)-x=[0.4(0.5x-3)]/(1/2)
25(0.5X-3)-x=2[0.4(0.5x-3)]
12.5X-75-x=0.8(0.5x-3)
125X-750-10x=8(0.5x-3)
115X-750=4x-24
111X=726
x=726/111

不对，我们学的最后是37／242