问题 解答题
求未知数x
①4x+7.1=12.5②4.5÷(x-0.51)=50③x:14%=1
3
7
:0.8.
答案

①4x+7.1=12.5,

  4x+7.1-7.1=12.5-7.1,

       4x÷4=5.4÷4,

           x=1.35;

②4.5÷(x-0.51)=50,

4.5÷(x-0.51)×(x-0.51)=50×(x-0.51),

              50×(x-0.51)=4.5,

          50×(x-0.51)÷50=4.5÷50,

               x-0.51+0.51=0.09+0.51,

                         x=0.6;

③x:14%=1

3
7
:0.8,

     0.8x=14%×1

3
7

0.8x÷0.8=

1
5
÷0.8,

        x=

1
4

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