| x | ( | x | + | 5 | ) | ( | x | + | 10 | ) | = | 26250 |
| Left side of the equation = | x | x | ( | x | + | 10 | ) | + | x | × | 5 | ( | x | + | 10 | ) |
| = | x | x | x | + | x | x | × | 10 | + | x | × | 5 | ( | x | + | 10 | ) |
| = | x | x | x | + | x | x | × | 10 | + | x | × | 5 | x | + | x | × | 5 | × | 10 |
| = | x | x | x | + | x | x | × | 10 | + | x | × | 5 | x | + | x | × | 50 |
| x | x | x | + | x | x | × | 10 | + | x | × | 5 | x | + | 50 | x | = | 26250 |