x/80 +6=x/50 -3
问题描述：
x/80 +6=x/50 -3
答
x/80-x/50=-3-6
(5x-8x)/400=-9
-3x/400=-9
左右约掉-3
x=3*400 =1200
答
x/80 +6=x/50 -3
x/50 -x/80=6+3
3/400x=9
x=3600/3
x=1200