解方程: 19-120%X=7 3/4x-5X%=17.5.

问题描述:

解方程:
19-120%X=7        

3
4
x-5X%=17.5.

(1)19-120%X=7   
     19-1.2X+1.2X=7+1.2X 
         1.2X+7-7=19-7
             1.2X=12
        1.2X÷1.2=12÷1.2
                X=10
(2)

3
4
x-5X%=17.5
0.75x-0.05x=17.5
       0.7x=17.5
  0.7x÷0.7=17.5÷0.7
          x=25