| 40 | × | 40 | ( | 30 | − | 20 | x | ) | × | 2 | = | 2 | − | 10 | ( | 5 | − | 20 | x | ) | × | 2 |
| 方程左边 = | 3200 | ( | 30 | − | 20 | x | ) |
| 3200 | ( | 30 | − | 20 | x | ) | = | 2 | − | 10 | ( | 5 | − | 20 | x | ) | × | 2 |
| 方程左边 = | 3200 | × | 30 | − | 3200 | × | 20 | x |
| = | 96000 | − | 64000 | x |
| 96000 | − | 64000 | x | = | 2 | − | 10 | ( | 5 | − | 20 | x | ) | × | 2 |
| 方程右边 = | 2 | − | 20 | ( | 5 | − | 20 | x | ) |
| 96000 | − | 64000 | x | = | 2 | − | 20 | ( | 5 | − | 20 | x | ) |
| 方程右边 = | 2 | − | 20 | × | 5 | + | 20 | × | 20 | x |
| = | 2 | − | 100 | + | 400 | x |
| = | - | 98 | + | 400 | x |
| 96000 | − | 64000 | x | = | - | 98 | + | 400 | x |
| - | 64000 | x | − | 400 | x | = | - | 98 | − | 96000 |
| - | 64400 | x | = | - | 98 | − | 96000 |
| - | 64400 | x | = | - | 96098 |
| 96098 | = | 64400 | x |
| 64400 | x | = | 96098 |
| x | = | 96098 | ÷ | 64400 |
| = | 96098 | × | 1 64400 |
| = | 48049 | × | 1 32200 |
| x | = | 48049 32200 |
| x | = | 1.492205 |