| ( | X | − | 5 | ) | × | 50 | = | 300 | + | 80 | × | 50 |
| Left side of the equation = | X | × | 50 | − | 5 | × | 50 |
| = | X | × | 50 | − | 250 |
| 50 | X | − | 250 | = | 300 | + | 80 | × | 50 |
| Right side of the equation = | 300 | + | 4000 |
| = | 4300 |
| 50 | X | − | 250 | = | 4300 |
| 50 | X | = | 4300 | + | 250 |
| 50 | X | = | 4550 |
| X | = | 4550 | ÷ | 50 |
| = | 4550 | × | 1 50 |
| = | 91 | × | 1 |
| X | = | 91 |