| ( | 2 | x | + | 20 | ) | ( | 2 | x | + | 20 | ) | = | 2249 |
| Left side of the equation = | 2 | x | ( | 2 | x | + | 20 | ) | + | 20 | ( | 2 | x | + | 20 | ) |
| = | 2 | x | × | 2 | x | + | 2 | x | × | 20 | + | 20 | ( | 2 | x | + | 20 | ) |
| = | 4 | x | x | + | 40 | x | + | 20 | ( | 2 | x | + | 20 | ) |
| = | 4 | x | x | + | 40 | x | + | 20 | × | 2 | x | + | 20 | × | 20 |
| = | 4 | x | x | + | 40 | x | + | 40 | x | + | 400 |
| = | 4 | x | x | + | 80 | x | + | 400 |
| 4 | x | x | + | 80 | x | + | 400 | = | 2249 |