| 4 | ( | 9 | ( | 6 | ( | x | + | 6 | ) | + | 10 | ) | + | 6 | ) | + | 15 | = | 7 | ( | - | 9 | x | + | 10 | ) | − | 49 |
| 方程左边 = | 4 | × | 9 | ( | 6 | ( | x | + | 6 | ) | + | 10 | ) | + | 4 | × | 6 | + | 15 |
| = | 36 | ( | 6 | ( | x | + | 6 | ) | + | 10 | ) | + | 24 | + | 15 |
| = | 36 | ( | 6 | ( | x | + | 6 | ) | + | 10 | ) | + | 39 |
| = | 36 | × | 6 | ( | x | + | 6 | ) | + | 36 | × | 10 | + | 39 |
| = | 216 | ( | x | + | 6 | ) | + | 360 | + | 39 |
| = | 216 | ( | x | + | 6 | ) | + | 399 |
| = | 216 | x | + | 216 | × | 6 | + | 399 |
| = | 216 | x | + | 1296 | + | 399 |
| = | 216 | x | + | 1695 |
| 216 | x | + | 1695 | = | 7 | ( | - | 9 | x | + | 10 | ) | − | 49 |
| 方程右边 = | - | 7 | × | 9 | x | + | 7 | × | 10 | − | 49 |
| = | - | 63 | x | + | 70 | − | 49 |
| = | - | 63 | x | + | 21 |
| 216 | x | + | 1695 | = | - | 63 | x | + | 21 |
| 216 | x | + | 63 | x | = | 21 | − | 1695 |
| 279 | x | = | 21 | − | 1695 |
| 279 | x | = | - | 1674 |
| x | = | - | 1674 | ÷ | 279 |
| = | - | 1674 | × | 1 279 |
| = | - | 6 | × | 1 |
| x | = | - | 6 |