求未知数x. 4x+7.1=12.5-2x 21x=21/67:9/67 13/7:0.8=x:14%

问题描述:

求未知数x.

4x+7.1=12.5-2x    21x=
21
67
9
67
1
3
7
:0.8=x:14%

(1)4x+7.1=12.5-2x,     4x+7.1+2x=12.5-2x+2x,        6x+7.1=12.5,    6x+7.1-7.1=12.5-7.1,     &...