问题 解答题

解下列方程.

5×0.7+3x=6.2

0.5(x-0.7x)=6.3

3x+1.7x=7.52

15(x+3)=141.

答案

(1)5×0.7+3x=6.2,

           3.5+3x=6.2,

               3x=6.2-3.5,

                x=2.7÷3,

                x=0.9;

(2)0.5(x-0.7x)=6.3

            x-0.7x=6.3×2,

              0.3x=12.6,

                 x=12.6÷0.3,

                 x=42;

(3)3x+1.7x=7.52,

        4.7x=7.52,

           x=7.52÷4.7,

           x=1.6;

(4)15(x+3)=141,

          x+3=141÷15,

            x=9.4-3,

            x=6.4.

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