| x | x | = | 12 | × | 12 | + | ( | x | − | 5 | ) | ( | x | − | 5 | ) |
| Right side of the equation = | 144 | + | ( | x | − | 5 | ) | ( | x | − | 5 | ) |
| x | x | = | 144 | + | ( | x | − | 5 | ) | ( | x | − | 5 | ) |
| Right side of the equation = | 144 | + | x | ( | x | − | 5 | ) | − | 5 | ( | x | − | 5 | ) |
| = | 144 | + | x | x | − | x | × | 5 | − | 5 | ( | x | − | 5 | ) |
| = | 144 | + | x | x | − | 5 | x | − | 5 | x | + | 5 | × | 5 |
| = | 144 | + | x | x | − | 5 | x | − | 5 | x | + | 25 |
| = | 169 | + | x | x | − | 10 | x |
| x | x | = | 169 | + | x | x | − | 10 | x |
| x= | 169 10 |