| 80 | × | 9 10 | x | = | 80 | × | 60 | + | 80 | × | 4 5 | ( | x | − | 60 | ) |
| Left side of the equation = | 72 | x |
| 72 | x | = | 80 | × | 60 | + | 80 | × | 4 5 | ( | x | − | 60 | ) |
| Right side of the equation = | 4800 | + | 64 | ( | x | − | 60 | ) |
| 72 | x | = | 4800 | + | 64 | ( | x | − | 60 | ) |
| Right side of the equation = | 4800 | + | 64 | x | − | 64 | × | 60 |
| = | 4800 | + | 64 | x | − | 3840 |
| = | 960 | + | 64 | x |
| 72 | x | = | 960 | + | 64 | x |
| 72 | x | − | 64 | x | = | 960 |
| 8 | x | = | 960 |
| x | = | 960 | ÷ | 8 |
| = | 960 | × | 1 8 |
| = | 120 | × | 1 |
| x | = | 120 |