解:解方程, 此方程的解为x = 145/2,【即x = 72.5】
1 + 百分之40x = 30
1 + (40/100)x = 30
1 + (2/5)x = 30
(2/5)x = 30 - 1
(2/5)x = 29
x = 29 ÷ 2/5
x = 29 × 5/2
x = 145/2
∴x = 72.5
答:此方程的解为x = 145/2,【即x = 72.5】
解方程步骤看图