| 92 | x | + | 80 | ( | 72 | − | x | ) | = | 85 | × | 72 |
| Left side of the equation = | 92 | x | + | 80 | × | 72 | − | 80 | x |
| = | 92 | x | + | 5760 | − | 80 | x |
| = | 12 | x | + | 5760 |
| 12 | x | + | 5760 | = | 85 | × | 72 |
| Right side of the equation = | 6120 |
| 12 | x | + | 5760 | = | 6120 |
| 12 | x | = | 6120 | − | 5760 |
| 12 | x | = | 360 |
| x | = | 360 | ÷ | 12 |
| = | 360 | × | 1 12 |
| = | 30 | × | 1 |
| x | = | 30 |