(80-x)2/7=40-x
问题描述:
(80-x)2/7=40-x
答
两边同时乘以7 然后左有同时拆括号 160-2x=280-7x 移项后 左边5x=280-160 x=120/5 x=24
答
(80-x)2/7=40-x
160/7-2x/7=40-x
x-2x/7=40-160/7
5x/7=120/7
x=120/7*7/5
x=24