解方程(x--40)乘(1+1/3)=x(1+12\100)最后答案250

变换为400*（x-40)=39x
解得 x=44.32

x+1/3x-40-40/3=x+12/100x
4/3x-160/3=28/25x
100/75x-84/75x=160/3
16/75x=160*25/75
x=250

(x-40)(1+1/3)=x(1+12/100)
(4/3)x-160/3=(112/100)x
(4/3-112/100)x=160/3
(64/300)x=160/3
x=250

(4/3)(x-40)=x(28/25)
两边乘75
100(x-40)=84x
100x-4000=84x
16x=4000
x=4000÷16
x=250