| - | 9 | ( | ( | - | 4 | − | x | ) | ( | - | 5 | ) | − | 4 | ) | − | ( | 2 | x | + | 10 | ) | ( | - | 10 | − | 8 | ) | = | 0 |
| 方程左边 = | - | 9 | ( | - | 4 | − | x | ) | ( | - | 5 | ) | + | 9 | × | 4 | − | ( | 2 | x | + | 10 | ) | ( | - | 10 | − | 8 | ) |
| = | - | 9 | ( | - | 4 | − | x | ) | ( | - | 5 | ) | + | 36 | − | ( | 2 | x | + | 10 | ) | ( | - | 10 | − | 8 | ) |
| = | 9 | × | 4 | ( | - | 5 | ) | + | 9 | x | ( | - | 5 | ) | + | 36 | − | ( | 2 | x | + | 10 | ) | ( | - | 10 | − | 8 | ) |
| = | 36 | ( | - | 5 | ) | + | 9 | x | ( | - | 5 | ) | + | 36 | − | ( | 2 | x | + | 10 | ) | ( | - | 10 | − | 8 | ) |
| = | - | 36 | × | 5 | + | 9 | x | ( | - | 5 | ) | + | 36 | − | ( | 2 | x | + | 10 | ) | ( | - | 10 | − | 8 | ) |
| = | - | 180 | + | 9 | x | ( | - | 5 | ) | + | 36 | − | ( | 2 | x | + | 10 | ) | ( | - | 10 | − | 8 | ) |
| = | - | 144 | + | 9 | x | ( | - | 5 | ) | − | ( | 2 | x | + | 10 | ) | ( | - | 10 | − | 8 | ) |
| = | - | 144 | − | 9 | x | × | 5 | − | ( | 2 | x | + | 10 | ) | ( | - | 10 | − | 8 | ) |
| = | - | 144 | − | 45 | x | − | ( | 2 | x | + | 10 | ) | ( | - | 10 | − | 8 | ) |
| = | - | 144 | − | 45 | x | − | 2 | x | ( | - | 10 | − | 8 | ) | − | 10 | ( | - | 10 | − | 8 | ) |
| = | - | 144 | − | 45 | x | + | 2 | x | × | 10 | + | 2 | x | × | 8 | − | 10 | ( | - | 10 | − | 8 | ) |
| = | - | 144 | − | 45 | x | + | 20 | x | + | 16 | x | − | 10 | ( | - | 10 | − | 8 | ) |
| = | - | 144 | − | 9 | x | − | 10 | ( | - | 10 | − | 8 | ) |
| = | - | 144 | − | 9 | x | + | 10 | × | 10 | + | 10 | × | 8 |
| = | - | 144 | − | 9 | x | + | 100 | + | 80 |
| = | 36 | − | 9 | x |
| 36 | − | 9 | x | = | 0 |
| - | 9 | x | = | 0 | − | 36 |
| - | 9 | x | = | - | 36 |
| 36 | = | 9 | x |
| 9 | x | = | 36 |
| x | = | 36 | ÷ | 9 |
| = | 36 | × | 1 9 |
| = | 4 | × | 1 |
| x | = | 4 |