| ( | ( | 7 100 | − | x | ) | ( | 7 10 | − | x | ) | ) | = | 1 | ÷ | 710 |
| Left side of the equation = | ( | 7 100 | − | x | ) | ( | 7 10 | − | x | ) |
| = | 7 100 | ( | 7 10 | − | x | ) | − | x | ( | 7 10 | − | x | ) |
| = | 7 100 | × | 7 10 | − | 7 100 | x | − | x | ( | 7 10 | − | x | ) |
| = | 49 1000 | − | 7 100 | x | − | x | ( | 7 10 | − | x | ) |
| = | 49 1000 | − | 7 100 | x | − | x | × | 7 10 | + | x | x |
| = | 49 1000 | − | 77 100 | x | + | x | x |
49 1000 | − | 77 100 | x | + | x | x | = | 1 | ÷ | 710 |
| Right side of the equation = | 1 710 |
49 1000 | − | 77 100 | x | + | x | x | = | 1 710 |