7 400000 | x | = | ( | 1 2 | − | x | ) | ( | 1 20 | − | x | ) |
| Right side of the equation = | 1 2 | ( | 1 20 | − | x | ) | − | x | ( | 1 20 | − | x | ) |
| = | 1 2 | × | 1 20 | − | 1 2 | x | − | x | ( | 1 20 | − | x | ) |
| = | 1 40 | − | 1 2 | x | − | x | ( | 1 20 | − | x | ) |
| = | 1 40 | − | 1 2 | x | − | x | × | 1 20 | + | x | x |
| = | 1 40 | − | 11 20 | x | + | x | x |
7 400000 | x | = | 1 40 | − | 11 20 | x | + | x | x |