| 20 | ( | 1 | + | x | ) | = | 16 | ( | 2 | + | x | ) |
| Left side of the equation = | 20 | × | 1 | + | 20 | x |
| = | 20 | + | 20 | x |
| 20 | + | 20 | x | = | 16 | ( | 2 | + | x | ) |
| Right side of the equation = | 16 | × | 2 | + | 16 | x |
| = | 32 | + | 16 | x |
| 20 | + | 20 | x | = | 32 | + | 16 | x |
| 20 | x | − | 16 | x | = | 32 | − | 20 |
| 4 | x | = | 32 | − | 20 |
| 4 | x | = | 12 |
| x | = | 12 | ÷ | 4 |
| = | 12 | × | 1 4 |
| = | 3 | × | 1 |
| x | = | 3 |