| ( | x | + | 10 | ) | × | 7 | ÷ | 2 | − | ( | ( | 10 | − | x | ) | × | 7 | ÷ | 2 | ) | = | 28 |
| Left side of the equation = | ( | x | + | 10 | ) | × | 7 2 | − | ( | ( | 10 | − | x | ) | × | 7 | ÷ | 2 | ) |
| ( | x | + | 10 | ) | × | 7 2 | − | ( | ( | 10 | − | x | ) | × | 7 | ÷ | 2 | ) | = | 28 |
| Left side of the equation = | x | × | 7 2 | + | 10 | × | 7 2 | − | ( | ( | 10 | − | x | ) | × | 7 | ÷ | 2 | ) |
| = | x | × | 7 2 | + | 35 | − | ( | ( | 10 | − | x | ) | × | 7 | ÷ | 2 | ) |
| = | 7 2 | x | + | 35 | − | ( | 10 | − | x | ) | × | 7 | ÷ | 2 |
| = | 7 2 | x | + | 35 | − | ( | 10 | − | x | ) | × | 7 2 |
| = | 7 2 | x | + | 35 | − | 10 | × | 7 2 | + | x | × | 7 2 |
| = | 7 2 | x | + | 35 | − | 35 | + | x | × | 7 2 |
| = | 7 | x | + | 0 |
| 7 | x | + | 0 | = | 28 |
| x | = | 28 | ÷ | 7 |
| = | 28 | × | 1 7 |
| = | 4 | × | 1 |
| x | = | 4 |