| ( | 3 | × | 45 | ) | x | + | 15 | ( | 2 | + | x | ) | = | 180 |
| Left side of the equation = | 3 | × | 45 | x | + | 15 | ( | 2 | + | x | ) |
| = | 135 | x | + | 15 | ( | 2 | + | x | ) |
| = | 135 | x | + | 15 | × | 2 | + | 15 | x |
| = | 135 | x | + | 30 | + | 15 | x |
| = | 150 | x | + | 30 |
| 150 | x | + | 30 | = | 180 |
| 150 | x | = | 180 | − | 30 |
| 150 | x | = | 150 |
| x | = | 150 | ÷ | 150 |
| = | 150 | × | 1 150 |
| = | 1 | × | 1 |
| x | = | 1 |