| 4 | x | − | 3 | ( | 20 | − | x | ) | = | 60 | − | 5 | ( | 9 | − | x | ) |
| Left side of the equation = | 4 | x | − | 3 | × | 20 | + | 3 | x |
| = | 4 | x | − | 60 | + | 3 | x |
| = | 7 | x | − | 60 |
| 7 | x | − | 60 | = | 60 | − | 5 | ( | 9 | − | x | ) |
| Right side of the equation = | 60 | − | 5 | × | 9 | + | 5 | x |
| = | 60 | − | 45 | + | 5 | x |
| = | 15 | + | 5 | x |
| 7 | x | − | 60 | = | 15 | + | 5 | x |
| 7 | x | − | 5 | x | = | 15 | + | 60 |
| 2 | x | = | 15 | + | 60 |
| 2 | x | = | 75 |
| x | = | 75 | ÷ | 2 |
| = | 75 | × | 1 2 |
| x | = | 75 2 |
| x | = | 37.5 |