| 3 | ( | x | + | 15 | ) | = | 15 | − | 5 | ( | x | − | 7 | ) |
| Left side of the equation = | 3 | x | + | 3 | × | 15 |
| = | 3 | x | + | 45 |
| 3 | x | + | 45 | = | 15 | − | 5 | ( | x | − | 7 | ) |
| Right side of the equation = | 15 | − | 5 | x | + | 5 | × | 7 |
| = | 15 | − | 5 | x | + | 35 |
| = | 50 | − | 5 | x |
| 3 | x | + | 45 | = | 50 | − | 5 | x |
| 3 | x | + | 5 | x | = | 50 | − | 45 |
| 8 | x | = | 50 | − | 45 |
| 8 | x | = | 5 |
| x | = | 5 | ÷ | 8 |
| = | 5 | × | 1 8 |
| x | = | 5 8 |
| x | = | 0.625 |