Question

解方程． (1)3×7+4x=25 (2)6x+18=48 (3)1.2x-0.9x=8.7 (4)9x-1.8=2.7

Answer 1

(1)3×7+4x=25 解：21+4x=25     21+4x-21=25-21           4x÷4=4÷4                     x=1          (2)6x+18=48   解：6x+18-18=48-18                   6x÷6=30÷6                                 x=5  (3)1.2x﹣0.9x=8.7                   解: 0.3x=8.7               0.3x÷0.3=8.7÷0.3                       x=29          (4)9x﹣1.8=2.7 解: 9x﹣1.8+1.8=2.7+1.8                    9x÷9=4.5÷9                           x=0.5