| ( | x | − | 4 | ) | + | ( | x | + | 4 | ) | + | x | ÷ | 4 | + | 4 | x | = | 625 |
| 方程左边 = | ( | x | − | 4 | ) | + | ( | x | + | 4 | ) | + | 17 4 | x |
| ( | x | − | 4 | ) | + | ( | x | + | 4 | ) | + | 17 4 | x | = | 625 |
| 方程左边 = | x | − | 4 | + | ( | x | + | 4 | ) | + | 17 4 | x |
| = | 21 4 | x | − | 4 | + | ( | x | + | 4 | ) |
| = | 21 4 | x | − | 4 | + | x | + | 4 |
| = | 25 4 | x | − | 0 |
25 4 | x | = | 625 |
| x | = | 625 | ÷ | 25 4 |
| = | 625 | × | 4 25 |
| = | 25 | × | 4 |
| x | = | 100 |