| 2660 | = | ( | ( | 4 | − | 8 5 | ) | × | 600 | + | x | ( | 6 | − | 7 2 | ) | ) | − | 1000 |
| Right side of the equation = | ( | 4 | − | 8 5 | ) | × | 600 | + | x | ( | 6 | − | 7 2 | ) | − | 1000 |
| = | 4 | × | 600 | − | 8 5 | × | 600 | + | x | ( | 6 | − | 7 2 | ) | − | 1000 |
| = | 2400 | − | 960 | + | x | ( | 6 | − | 7 2 | ) | − | 1000 |
| = | 440 | + | x | ( | 6 | − | 7 2 | ) |
| = | 440 | + | x | × | 6 | − | x | × | 7 2 |
| = | 440 | + | 5 2 | x |
| 2660 | = | 440 | + | 5 2 | x |
| - | 5 2 | x | = | 440 | − | 2660 |
| - | 5 2 | x | = | - | 2220 |
| 2220 | = | 5 2 | x |
5 2 | x | = | 2220 |
| x | = | 2220 | ÷ | 5 2 |
| = | 2220 | × | 2 5 |
| = | 444 | × | 2 |
| x | = | 888 |