| s | ( | s | − | 3 | ) | = | ( | s | + | 1 | ) | ( | 2 | s | − | 3 | ) |
| Left side of the equation = | s | s | − | s | × | 3 |
| s | s | − | 3 | s | = | ( | s | + | 1 | ) | ( | 2 | s | − | 3 | ) |
| Right side of the equation = | s | ( | 2 | s | − | 3 | ) | + | 1 | ( | 2 | s | − | 3 | ) |
| = | s | × | 2 | s | − | s | × | 3 | + | 1 | ( | 2 | s | − | 3 | ) |
| = | s | × | 2 | s | − | 3 | s | + | 1 | × | 2 | s | − | 1 | × | 3 |
| = | s | × | 2 | s | − | 3 | s | + | 2 | s | − | 3 |
| = | s | × | 2 | s | − | 1 | s | − | 3 |
| s | s | − | 3 | s | = | s | × | 2 | s | − | 1 | s | − | 3 |