100 | × | 20 | + | x | × | 45 | = | ( | 100 | + | x | ) | × | 25 |
方程左边 = | 2000 | + | x | × | 45 |
2000 | + | 45 | x | = | ( | 100 | + | x | ) | × | 25 |
方程右边 = | 100 | × | 25 | + | x | × | 25 |
= | 2500 | + | x | × | 25 |
2000 | + | 45 | x | = | 2500 | + | 25 | x |
45 | x | − | 25 | x | = | 2500 | − | 2000 |
20 | x | = | 2500 | − | 2000 |
20 | x | = | 500 |
x | = | 500 | ÷ | 20 |
= | 500 | × | 1 20 |
= | 25 | × | 1 |
x | = | 25 |