| - | 450 | − | x | − | 690 | − | x | × | 8 100 | ÷ | 4 | = | 0 |
| Left side of the equation = | - | 450 | − | x | − | 690 | − | x | × | 1 50 |
| = | - | 1140 | − | 51 50 | x |
| - | 1140 | − | 51 50 | x | = | 0 |
| - | 51 50 | x | = | 0 | + | 1140 |
| - | 51 50 | x | = | 1140 |
| - | 1140 | = | 51 50 | x |
51 50 | x | = | - | 1140 |
| x | = | - | 1140 | ÷ | 51 50 |
| = | - | 1140 | × | 50 51 |
| = | - | 380 | × | 50 17 |
| x | = | - | 19000 17 |
| x | = | - 1117.647059 |