解方程: (1)5x-18.5=1.3x (2)15:1/2=3x:4/5.

问题描述:

解方程:
(1)5x-18.5=1.3x
(2)15:

1
2
=3x:
4
5

(1)5x-18.5=1.3x
   5x-18.5+18.5=1.3x+18.5
        5x-1.3x=1.3x-1.3x+18.5
           3.7x=18.5
      3.7x÷3.7=18.5÷3.7
              x=5;
(2)15:

1
2
=3x:
4
5

        
3
2
x=15×
4
5

     
3
2
x÷
3
2
=12÷
3
2

         x=8.