| 5 | ( | ( | 3 2 | x | − | 30 | ) | × | 4 5 | − | x | ) | = | ( | 3 2 | x | − | x | ) | + | 130 |
| 方程左边 = | 5 | ( | 3 2 | x | − | 30 | ) | × | 4 5 | − | 5 | x |
| = | 4 | ( | 3 2 | x | − | 30 | ) | − | 5 | x |
| = | 4 | × | 3 2 | x | − | 4 | × | 30 | − | 5 | x |
| = | 6 | x | − | 120 | − | 5 | x |
| = | 1 | x | − | 120 |
| 1 | x | − | 120 | = | ( | 3 2 | x | − | x | ) | + | 130 |
| 方程右边 = | 3 2 | x | − | x | + | 130 |
| = | 1 2 | x | + | 130 |
| 1 | x | − | 120 | = | 1 2 | x | + | 130 |
| 1 | x | − | 1 2 | x | = | 130 | + | 120 |
1 2 | x | = | 130 | + | 120 |
1 2 | x | = | 250 |
| x | = | 250 | ÷ | 1 2 |
| = | 250 | × | 2 |
| x | = | 500 |