| ( | x | − | 10 | ) | ÷ | 2 | = | 120 | − | x | + | 10 |
| Left side of the equation = | x | × | 1 2 | − | 10 | × | 1 2 |
| = | x | × | 1 2 | − | 5 |
1 2 | x | − | 5 | = | 120 | − | x | + | 10 |
| Right side of the equation = | 130 | − | x |
1 2 | x | − | 5 | = | 130 | − | x |
1 2 | x | + | x | = | 130 | + | 5 |
3 2 | x | = | 130 | + | 5 |
3 2 | x | = | 135 |
| x | = | 135 | ÷ | 3 2 |
| = | 135 | × | 2 3 |
| = | 45 | × | 2 |
| x | = | 90 |