| 7 | ( | ( | s | − | 1400 | ) | ÷ | 200 | ) | = | 8 | ( | ( | s | − | 1600 | ) | ÷ | 300 | ) |
| Left side of the equation = | 7 | ( | s | − | 1400 | ) | ÷ | 200 |
| = | 7 200 | ( | s | − | 1400 | ) |
| = | 7 200 | s | − | 7 200 | × | 1400 |
| = | 7 200 | s | − | 49 |
7 200 | s | − | 49 | = | 8 | ( | ( | s | − | 1600 | ) | ÷ | 300 | ) |
| Right side of the equation = | 8 | ( | s | − | 1600 | ) | ÷ | 300 |
| = | 2 75 | ( | s | − | 1600 | ) |
| = | 2 75 | s | − | 2 75 | × | 1600 |
| = | 2 75 | s | − | 128 3 |
7 200 | s | − | 49 | = | 2 75 | s | − | 128 3 |
7 200 | s | − | 2 75 | s | = | - | 128 3 | + | 49 |
1 120 | s | = | - | 128 3 | + | 49 |
1 120 | s | = | 19 3 |
| s | = | 19 3 | ÷ | 1 120 |
| = | 19 3 | × | 120 |
| = | 19 | × | 40 |
| s | = | 760 |