| ( | 42 | + | x | ) | ( | 42 | − | x | ) | ÷ | 42 | × | x | = | 23 |
| Left side of the equation = | 42 | ( | 42 | − | x | ) | × | 1 42 | x | + | x | ( | 42 | − | x | ) | × | 1 42 | x |
| = | 1 | ( | 42 | − | x | ) | x | + | x | ( | 42 | − | x | ) | × | 1 42 | x |
| = | 1 | × | 42 | x | − | 1 | x | x | + | x | ( | 42 | − | x | ) | × | 1 42 | x |
| = | 42 | x | − | 1 | x | x | + | x | ( | 42 | − | x | ) | × | 1 42 | x |
| = | 42 | x | − | 1 | x | x | + | x | × | 42 | × | 1 42 | x | − | x | x | × | 1 42 |
| = | 42 | x | − | 1 | x | x | + | x | × | 1 | x | − | x | x | × | 1 42 | x |
| 42 | x | − | 1 | x | x | + | x | × | 1 | x | − | x | x | × | 1 42 | x | = | 23 |