| ( | 2 | ( | 37 | − | x | ) | + | 4 | ) | ( | x | − | 25 | ) | = | 90 |
| Left side of the equation = | 2 | ( | 37 | − | x | ) | ( | x | − | 25 | ) | + | 4 | ( | x | − | 25 | ) |
| = | 2 | × | 37 | ( | x | − | 25 | ) | − | 2 | x | ( | x | − | 25 | ) | + | 4 | ( | x | − | 25 | ) |
| = | 74 | ( | x | − | 25 | ) | − | 2 | x | ( | x | − | 25 | ) | + | 4 | ( | x | − | 25 | ) |
| = | 74 | x | − | 74 | × | 25 | − | 2 | x | ( | x | − | 25 | ) | + | 4 | ( | x | − | 25 | ) |
| = | 74 | x | − | 1850 | − | 2 | x | ( | x | − | 25 | ) | + | 4 | ( | x | − | 25 | ) |
| = | 74 | x | − | 1850 | − | 2 | x | x | + | 2 | x | × | 25 | + | 4 | ( | x | − | 25 | ) |
| = | 74 | x | − | 1850 | − | 2 | x | x | + | 50 | x | + | 4 | ( | x | − | 25 | ) |
| = | 124 | x | − | 1850 | − | 2 | x | x | + | 4 | ( | x | − | 25 | ) |
| = | 124 | x | − | 1850 | − | 2 | x | x | + | 4 | x | − | 4 | × | 25 |
| = | 124 | x | − | 1850 | − | 2 | x | x | + | 4 | x | − | 100 |
| = | 128 | x | − | 1950 | − | 2 | x | x |
| 128 | x | − | 1950 | − | 2 | x | x | = | 90 |