| 10 | x | + | ( | x | + | 2 | ) | − | ( | 10 | ( | x | + | 2 | ) | + | x | ) | = | 138 |
| 方程左边 = | 10 | x | + | x | + | 2 | − | ( | 10 | ( | x | + | 2 | ) | + | x | ) |
| = | 11 | x | + | 2 | − | ( | 10 | ( | x | + | 2 | ) | + | x | ) |
| = | 11 | x | + | 2 | − | 10 | ( | x | + | 2 | ) | − | x |
| = | 10 | x | + | 2 | − | 10 | ( | x | + | 2 | ) |
| = | 10 | x | + | 2 | − | 10 | x | − | 10 | × | 2 |
| = | 10 | x | + | 2 | − | 10 | x | − | 20 |
| = | 0 | x | − | 18 |
| - | 18 | = | 138 |
| = | 138 | + | 18 |