| 2 | ( | 3 | x | − | 4 | ) | + | 7 | ( | 4 | − | x | ) | = | 4 | x |
| Left side of the equation = | 2 | × | 3 | x | − | 2 | × | 4 | + | 7 | ( | 4 | − | x | ) |
| = | 6 | x | − | 8 | + | 7 | ( | 4 | − | x | ) |
| = | 6 | x | − | 8 | + | 7 | × | 4 | − | 7 | x |
| = | 6 | x | − | 8 | + | 28 | − | 7 | x |
| = | - | 1 | x | + | 20 |
| - | 1 | x | + | 20 | = | 4 | x |
| - | 1 | x | − | 4 | x | = | - | 20 |
| - | 5 | x | = | - | 20 |
| 20 | = | 5 | x |
| 5 | x | = | 20 |
| x | = | 20 | ÷ | 5 |
| = | 20 | × | 1 5 |
| = | 4 | × | 1 |
| x | = | 4 |