| ( | 8 | + | 2 | x | ) | ( | 6 | + | 2 | x | ) | = | 90 |
| Left side of the equation = | 8 | ( | 6 | + | 2 | x | ) | + | 2 | x | ( | 6 | + | 2 | x | ) |
| = | 8 | × | 6 | + | 8 | × | 2 | x | + | 2 | x | ( | 6 | + | 2 | x | ) |
| = | 48 | + | 16 | x | + | 2 | x | ( | 6 | + | 2 | x | ) |
| = | 48 | + | 16 | x | + | 2 | x | × | 6 | + | 2 | x | × | 2 | x |
| = | 48 | + | 16 | x | + | 12 | x | + | 4 | x | x |
| = | 48 | + | 28 | x | + | 4 | x | x |
| 48 | + | 28 | x | + | 4 | x | x | = | 90 |