| 360 | + | 1200 | × | 10 | ÷ | x | − | 800 | = | 640 |
| Multiply both sides of the equation by: | x |
| 360 | x | + | 1200 | × | 10 | − | 800 | x | = | 640 | x |
| 360 | x | − | 800 | x | − | 640 | x | = | - | 1200 | × | 10 |
| 360 | x | − | 800 | x | − | 640 | x | = | - | 12000 |
| - | 1080 | x | = | - | 12000 |
| 12000 | = | 1080 | x |
| 1080 | x | = | 12000 |
| x | = | 12000 | ÷ | 1080 |
| = | 12000 | × | 1 1080 |
| = | 100 | × | 1 9 |
| x | = | 100 9 |
| x | = | 11.111111 |