| 3 | ( | x | + | 5 | ) | = | 4 | ( | 2 | x | − | 5 | ) |
| Left side of the equation = | 3 | x | + | 3 | × | 5 |
| = | 3 | x | + | 15 |
| 3 | x | + | 15 | = | 4 | ( | 2 | x | − | 5 | ) |
| Right side of the equation = | 4 | × | 2 | x | − | 4 | × | 5 |
| = | 8 | x | − | 20 |
| 3 | x | + | 15 | = | 8 | x | − | 20 |
| 3 | x | − | 8 | x | = | - | 20 | − | 15 |
| - | 5 | x | = | - | 20 | − | 15 |
| - | 5 | x | = | - | 35 |
| 35 | = | 5 | x |
| 5 | x | = | 35 |
| x | = | 35 | ÷ | 5 |
| = | 35 | × | 1 5 |
| = | 7 | × | 1 |
| x | = | 7 |