| ( | x | + | 40 | ) | × | 4 5 | = | ( | x | + | 12 | ) |
| Left side of the equation = | x | × | 4 5 | + | 40 | × | 4 5 |
| = | x | × | 4 5 | + | 32 |
4 5 | x | + | 32 | = | ( | x | + | 12 | ) |
| Right side of the equation = | x | + | 12 |
4 5 | x | + | 32 | = | x | + | 12 |
4 5 | x | − | x | = | 12 | − | 32 |
| - | 1 5 | x | = | 12 | − | 32 |
| - | 1 5 | x | = | - | 20 |
| 20 | = | 1 5 | x |
1 5 | x | = | 20 |
| x | = | 20 | ÷ | 1 5 |
| = | 20 | × | 5 |
| x | = | 100 |