| 4 | ( | x | + | 3 | ) | ( | x | + | 3 | ) | = | 25 | ( | x | − | 2 | ) | ( | x | − | 2 | ) |
| Left side of the equation = | 4 | x | ( | x | + | 3 | ) | + | 4 | × | 3 | ( | x | + | 3 | ) |
| = | 4 | x | ( | x | + | 3 | ) | + | 12 | ( | x | + | 3 | ) |
| = | 4 | x | x | + | 4 | x | × | 3 | + | 12 | ( | x | + | 3 | ) |
| = | 4 | x | x | + | 12 | x | + | 12 | ( | x | + | 3 | ) |
| = | 4 | x | x | + | 12 | x | + | 12 | x | + | 12 | × | 3 |
| = | 4 | x | x | + | 12 | x | + | 12 | x | + | 36 |
| = | 4 | x | x | + | 24 | x | + | 36 |
| 4 | x | x | + | 24 | x | + | 36 | = | 25 | ( | x | − | 2 | ) | ( | x | − | 2 | ) |
| Right side of the equation = | 25 | x | ( | x | − | 2 | ) | − | 25 | × | 2 | ( | x | − | 2 | ) |
| = | 25 | x | ( | x | − | 2 | ) | − | 50 | ( | x | − | 2 | ) |
| = | 25 | x | x | − | 25 | x | × | 2 | − | 50 | ( | x | − | 2 | ) |
| = | 25 | x | x | − | 50 | x | − | 50 | ( | x | − | 2 | ) |
| = | 25 | x | x | − | 50 | x | − | 50 | x | + | 50 | × | 2 |
| = | 25 | x | x | − | 50 | x | − | 50 | x | + | 100 |
| = | 25 | x | x | − | 100 | x | + | 100 |
| 4 | x | x | + | 24 | x | + | 36 | = | 25 | x | x | − | 100 | x | + | 100 |
| x1= | 4 7 |
| x2= | 16 3 |