| ( | 6 | + | x | ) | ( | 8 | + | x | ) | = | 48 | + | 51 |
| Left side of the equation = | 6 | ( | 8 | + | x | ) | + | x | ( | 8 | + | x | ) |
| = | 6 | × | 8 | + | 6 | x | + | x | ( | 8 | + | x | ) |
| = | 48 | + | 6 | x | + | x | ( | 8 | + | x | ) |
| = | 48 | + | 6 | x | + | x | × | 8 | + | x | x |
| = | 48 | + | 14 | x | + | x | x |
| 48 | + | 14 | x | + | x | x | = | 48 | + | 51 |
| Right side of the equation = | 99 |
| 48 | + | 14 | x | + | x | x | = | 99 |