| ( | 44 | + | x | − | 25 | ) | ( | 48 | − | x | ) | = | 0 |
| 方程左边 = | 44 | ( | 48 | − | x | ) | + | x | ( | 48 | − | x | ) | − | 25 | ( | 48 | − | x | ) |
| = | 44 | × | 48 | − | 44 | x | + | x | ( | 48 | − | x | ) | − | 25 | ( | 48 | − | x | ) |
| = | 2112 | − | 44 | x | + | x | ( | 48 | − | x | ) | − | 25 | ( | 48 | − | x | ) |
| = | 2112 | − | 44 | x | + | x | × | 48 | − | x | x | − | 25 | ( | 48 | − | x | ) |
| = | 2112 | + | 4 | x | − | x | x | − | 25 | ( | 48 | − | x | ) |
| = | 2112 | + | 4 | x | − | x | x | − | 25 | × | 48 | + | 25 | x |
| = | 2112 | + | 4 | x | − | x | x | − | 1200 | + | 25 | x |
| = | 912 | + | 29 | x | − | x | x |
| 912 | + | 29 | x | − | x | x | = | 0 |