| ( | 2 | x | + | 20 | ) | ( | 2 | x | + | 30 | ) | = | 3000 |
| Left side of the equation = | 2 | x | ( | 2 | x | + | 30 | ) | + | 20 | ( | 2 | x | + | 30 | ) |
| = | 2 | x | × | 2 | x | + | 2 | x | × | 30 | + | 20 | ( | 2 | x | + | 30 | ) |
| = | 4 | x | x | + | 60 | x | + | 20 | ( | 2 | x | + | 30 | ) |
| = | 4 | x | x | + | 60 | x | + | 20 | × | 2 | x | + | 20 | × | 30 |
| = | 4 | x | x | + | 60 | x | + | 40 | x | + | 600 |
| = | 4 | x | x | + | 100 | x | + | 600 |
| 4 | x | x | + | 100 | x | + | 600 | = | 3000 |