解方程. 6:22/3=x:4 x:10/7=0.3:12 7×(13-x)=3x.

问题描述:

解方程.
6:2

2
3
=x:4                 
x:
10
7
=0.3:12               
7×(13-x)=3x.

(1)6:2

2
3
=x:4
          2
2
3
x=6×4
      2
2
3
x÷2
2
3
=24÷2
2
3

             x=9;
(2)x:
10
7
=0.3:12
       12x=
10
7
×0.3
   12x÷12=
3
7
÷12
         x=
1
28

(3)7×(13-x)=3x
          91-7x=3x
       91-7x+7x=3x+7x
         91÷10=10x÷10
              x=9.1.