| 56 | x | − | ( | 580 | + | 40 | x | ) | − | ( | 13 100 | x | − | 5 | ) | × | 3 25 | x | = | 120 |
| Left side of the equation = | 56 | x | − | 580 | − | 40 | x | − | ( | 13 100 | x | − | 5 | ) | × | 3 25 | x |
| = | 16 | x | − | 580 | − | ( | 13 100 | x | − | 5 | ) | × | 3 25 | x |
| = | 16 | x | − | 580 | − | 13 100 | x | × | 3 25 | x | + | 5 | × | 3 25 | x |
| = | 16 | x | − | 580 | − | 39 2500 | x | x | + | 3 5 | x |
| = | 83 5 | x | − | 580 | − | 39 2500 | x | x |
83 5 | x | − | 580 | − | 39 2500 | x | x | = | 120 |