| x | + | 50 | = | 2 | ( | ( | 450 | − | x | ) | − | 50 | ) |
| Right side of the equation = | 2 | ( | 450 | − | x | ) | − | 2 | × | 50 |
| = | 2 | ( | 450 | − | x | ) | − | 100 |
| = | 2 | × | 450 | − | 2 | x | − | 100 |
| = | 900 | − | 2 | x | − | 100 |
| = | 800 | − | 2 | x |
| x | + | 50 | = | 800 | − | 2 | x |
| x | + | 2 | x | = | 800 | − | 50 |
| 3 | x | = | 800 | − | 50 |
| 3 | x | = | 750 |
| x | = | 750 | ÷ | 3 |
| = | 750 | × | 1 3 |
| = | 250 | × | 1 |
| x | = | 250 |