3x-2=1.6 5x÷2=25 x-18=2.9+0.71 8x+x=2.97 14x-3x=1.21 1.6×25-5x=2

问题描述:

3x-2=1.6   5x÷2=25   x-18=2.9+0.71
8x+x=2.97   14x-3x=1.21   1.6×25-5x=2

(1)3x-2=1.6,
       3x-2+2=1.6+2,
           3x=3.6,
        3x÷3=3.6÷3,
             x=1.2;
(2)5x÷2=25,
  5x÷2×2=25×2,
        5x=50,
     5x÷5=50÷5,
         x=10;
(3)x-18=2.9+0.71,
  x-18+18=3.61+18,
        x=21.61;
(4)8x+x=2.97,
       9x=2.97,
    9x÷9=2.97÷9,
        x=0.33;
(5)14x-3x=1.21,
        11x=1.21,
    11x÷11=1.21÷11,
          x=0.11;
(6)1.6×25-5x=2,
          40-5x=2,
       40-5x+5x=2+5x,
           2+5x=40,
         2+5x-2=40-2,
             5x=38,
          5x÷5=38÷5,
              x=7.2.