| ( | 10080 | − | 10080 | x | − | 1120 | − | 2240 | + | 2800 | ) | ( | 1 | − | x | ) | = | 4200 |
| Left side of the equation = | 10080 | ( | 1 | − | x | ) | − | 10080 | x | ( | 1 | − | x | ) | − | 1120 | ( | 1 | − | x | ) | − | 2240 | ( | 1 | − | x | ) | + | 2800 | ( | 1 | − | x | ) |
| = | 10080 | × | 1 | − | 10080 | x | − | 10080 | x | ( | 1 | − | x | ) | − | 1120 | ( | 1 | − | x | ) | − | 2240 | ( | 1 | − | x | ) | + | 2800 |
| = | 10080 | − | 10080 | x | − | 10080 | x | ( | 1 | − | x | ) | − | 1120 | ( | 1 | − | x | ) | − | 2240 | ( | 1 | − | x | ) | + | 2800 | ( | 1 | − | x | ) |
| = | 10080 | − | 10080 | x | − | 10080 | x | × | 1 | + | 10080 | x | x | − | 1120 | ( | 1 | − | x | ) | − | 2240 |
| = | 10080 | − | 10080 | x | − | 10080 | x | + | 10080 | x | x | − | 1120 | ( | 1 | − | x | ) | − | 2240 | ( | 1 | − | x | ) |
| = | 10080 | − | 20160 | x | + | 10080 | x | x | − | 1120 | ( | 1 | − | x | ) | − | 2240 | ( | 1 | − | x | ) | + | 2800 | ( | 1 | − | x | ) |
| = | 10080 | − | 20160 | x | + | 10080 | x | x | − | 1120 | × | 1 | + | 1120 | x | − | 2240 | ( | 1 | − | x | ) |
| = | 10080 | − | 20160 | x | + | 10080 | x | x | − | 1120 | + | 1120 | x | − | 2240 | ( | 1 | − | x | ) | + | 2800 |
| = | 8960 | − | 19040 | x | + | 10080 | x | x | − | 2240 | ( | 1 | − | x | ) | + | 2800 | ( | 1 | − | x | ) |
| = | 8960 | − | 19040 | x | + | 10080 | x | x | − | 2240 | × | 1 | + | 2240 | x | + | 2800 | ( | 1 | − | x | ) |
| = | 8960 | − | 19040 | x | + | 10080 | x | x | − | 2240 | + | 2240 | x | + | 2800 | ( | 1 | − | x | ) |
| = | 6720 | − | 16800 | x | + | 10080 | x | x | + | 2800 | ( | 1 | − | x | ) |
| = | 6720 | − | 16800 | x | + | 10080 | x | x | + | 2800 | × | 1 | − | 2800 | x |
| = | 6720 | − | 16800 | x | + | 10080 | x | x | + | 2800 | − | 2800 | x |
| = | 9520 | − | 19600 | x | + | 10080 | x | x |
| 9520 | − | 19600 | x | + | 10080 | x | x | = | 4200 |