| ( | x | + | 2 | ) | ( | x | + | 3 | ) | ( | x | + | 4 | ) | = | 990 |
| Left side of the equation = | x | ( | x | + | 3 | ) | ( | x | + | 4 | ) | + | 2 | ( | x | + | 3 | ) | ( | x | + | 4 | ) |
| = | x | x | ( | x | + | 4 | ) | + | x | × | 3 | ( | x | + | 4 | ) | + | 2 | ( | x | + | 3 | ) | ( | x | + | 4 | ) |
| = | x | x | x | + | x | x | × | 4 | + | x | × | 3 | ( | x | + | 4 | ) | + | 2 | ( | x | + | 3 | ) | ( | x | + | 4 | ) |
| = | x | x | x | + | x | x | × | 4 | + | x | × | 3 | x | + | x | × | 3 | × | 4 |
| = | x | x | x | + | x | x | × | 4 | + | x | × | 3 | x | + | x | × | 12 | + | 2 |
| = | x | x | x | + | x | x | × | 4 | + | x | × | 3 | x | + | 12 | x | + | 2 |
| = | x | x | x | + | x | x | × | 4 | + | x | × | 3 | x | + | 12 | x | + | 2 |
| = | x | x | x | + | x | x | × | 4 | + | x | × | 3 | x | + | 12 | x | + | 2 |
| = | x | x | x | + | x | x | × | 4 | + | x | × | 3 | x | + | 12 | x | + | 2 |
| = | x | x | x | + | x | x | × | 4 | + | x | × | 3 | x | + | 20 | x | + | 2 |
| = | x | x | x | + | x | x | × | 4 | + | x | × | 3 | x | + | 20 | x | + | 2 |
| = | x | x | x | + | x | x | × | 4 | + | x | × | 3 | x | + | 20 | x | + | 2 |
| = | x | x | x | + | x | x | × | 4 | + | x | × | 3 | x | + | 26 | x | + | 2 |
| x | x | x | + | x | x | × | 4 | + | x | × | 3 | x | + | 26 | x | + | 2 | = | 990 |