| ( | 8 | + | x | ) | ( | 16 | + | 2 | x | ) | = | 625 2 |
| Left side of the equation = | 8 | ( | 16 | + | 2 | x | ) | + | x | ( | 16 | + | 2 | x | ) |
| = | 8 | × | 16 | + | 8 | × | 2 | x | + | x | ( | 16 | + | 2 | x | ) |
| = | 128 | + | 16 | x | + | x | ( | 16 | + | 2 | x | ) |
| = | 128 | + | 16 | x | + | x | × | 16 | + | x | × | 2 | x |
| = | 128 | + | 32 | x | + | x | × | 2 | x |
| 128 | + | 32 | x | + | x | × | 2 | x | = | 625 2 |
| x1= | - | 41 2 |
| x2= | 9 2 |