| ( | 1 5 | − | 2 | x | ) | ( | 1 5 | − | 2 | x | ) | = | 20000000000000 | x |
| Left side of the equation = | 1 5 | ( | 1 5 | − | 2 | x | ) | − | 2 | x | ( | 1 5 | − | 2 | x | ) |
| = | 1 5 | × | 1 5 | − | 1 5 | × | 2 | x | − | 2 | x | ( | 1 5 | − | 2 | x | ) |
| = | 1 25 | − | 2 5 | x | − | 2 | x | ( | 1 5 | − | 2 | x | ) |
| = | 1 25 | − | 2 5 | x | − | 2 | x | × | 1 5 | + | 2 | x | × | 2 | x |
| = | 1 25 | − | 2 5 | x | − | 2 5 | x | + | 4 | x | x |
| = | 1 25 | − | 4 5 | x | + | 4 | x | x |
1 25 | − | 4 5 | x | + | 4 | x | x | = | 20000000000000 | x |