解方程. 2.5X-1.4=5.6 7.8X-4.8X=12.

问题描述:

解方程.
2.5X-1.4=5.6                  
7.8X-4.8X=12.

(1)2.5X-1.4=5.6,
     2.5X-1.4+1.4=5.6+1.4,
        2.5x÷2.5=7÷2.5,
                x=2.8;
(2)7.8X-4.8X=12,
         3x÷3=12÷3,
             x=4.