| 3 | ( | 35 | + | x | ) | = | 5 | ( | 15 | + | x | ) |
| Left side of the equation = | 3 | × | 35 | + | 3 | x |
| = | 105 | + | 3 | x |
| 105 | + | 3 | x | = | 5 | ( | 15 | + | x | ) |
| Right side of the equation = | 5 | × | 15 | + | 5 | x |
| = | 75 | + | 5 | x |
| 105 | + | 3 | x | = | 75 | + | 5 | x |
| 3 | x | − | 5 | x | = | 75 | − | 105 |
| - | 2 | x | = | 75 | − | 105 |
| - | 2 | x | = | - | 30 |
| 30 | = | 2 | x |
| 2 | x | = | 30 |
| x | = | 30 | ÷ | 2 |
| = | 30 | × | 1 2 |
| = | 15 | × | 1 |
| x | = | 15 |