| ( | 100 | − | x | ) | × | 60 | = | ( | 100 | − | x | − | 4 | ) | ( | 60 | + | 3 | × | 4 | ) |
| 方程左边 = | 100 | × | 60 | − | x | × | 60 |
| = | 6000 | − | x | × | 60 |
| 6000 | − | 60 | x | = | ( | 100 | − | x | − | 4 | ) | ( | 60 | + | 3 | × | 4 | ) |
| 方程右边 = | 100 | ( | 60 | + | 3 | × | 4 | ) | − | x | ( | 60 | + | 3 | × | 4 | ) | − | 4 | ( | 60 | + | 3 | × | 4 | ) |
| = | 100 | × | 60 | + | 100 | × | 3 | × | 4 | − | x | ( | 60 | + | 3 | × | 4 | ) | − | 4 | ( | 60 | + | 3 | × | 4 | ) |
| = | 6000 | + | 1200 | − | x | ( | 60 | + | 3 | × | 4 | ) | − | 4 | ( | 60 | + | 3 | × | 4 | ) |
| = | 7200 | − | x | ( | 60 | + | 3 | × | 4 | ) | − | 4 | ( | 60 | + | 3 | × | 4 | ) |
| = | 7200 | − | x | × | 60 | − | x | × | 3 | × | 4 | − | 4 | ( | 60 | + | 3 | × | 4 | ) |
| = | 7200 | − | x | × | 60 | − | x | × | 12 | − | 4 | ( | 60 | + | 3 | × | 4 | ) |
| = | 7200 | − | 72 | x | − | 4 | ( | 60 | + | 3 | × | 4 | ) |
| = | 7200 | − | 72 | x | − | 4 | × | 60 | − | 4 | × | 3 | × | 4 |
| = | 7200 | − | 72 | x | − | 240 | − | 48 |
| = | 6912 | − | 72 | x |
| 6000 | − | 60 | x | = | 6912 | − | 72 | x |
| - | 60 | x | + | 72 | x | = | 6912 | − | 6000 |
| 12 | x | = | 6912 | − | 6000 |
| 12 | x | = | 912 |
| x | = | 912 | ÷ | 12 |
| = | 912 | × | 1 12 |
| = | 76 | × | 1 |
| x | = | 76 |