解方程. x×(1-1/5)=80 x+1/4x=60.

问题描述:

解方程.
x×(1-

1
5
)=80
x+
1
4
x=60.

(1)x×(1-

1
5
)=80,
                
4
5
x=80,
            
4
5
4
5
=80÷
4
5

                   x=100;
(2)x+
1
4
x=60,
      
5
4
x=60,
  
5
4
5
4
=60÷
5
4

         x=48.