| w | = | ( | 7 | − | 4 | ) | ( | - | 50 | × | 7 | + | 1200 | ) |
| Right side of the equation = | 7 | ( | - | 50 | × | 7 | + | 1200 | ) | − | 4 | ( | - | 50 | × | 7 | + | 1200 | ) |
| = | - | 7 | × | 50 | × | 7 | + | 7 | × | 1200 | − | 4 | ( | - | 50 | × | 7 | + | 1200 | ) |
| = | - | 2450 | + | 8400 | − | 4 | ( | - | 50 | × | 7 | + | 1200 | ) |
| = | 5950 | − | 4 | ( | - | 50 | × | 7 | + | 1200 | ) |
| = | 5950 | + | 4 | × | 50 | × | 7 | − | 4 | × | 1200 |
| = | 5950 | + | 1400 | − | 4800 |
| = | 2550 |
| w | = | 2550 |