| ( | 22 | + | x | ) | ( | 29 | + | x | ) | − | 29 | × | 22 | = | 22 | × | 29 | ÷ | 4 |
| Left side of the equation = | ( | 22 | + | x | ) | ( | 29 | + | x | ) | − | 638 |
| ( | 22 | + | x | ) | ( | 29 | + | x | ) | − | 638 | = | 22 | × | 29 | ÷ | 4 |
| Left side of the equation = | 22 | ( | 29 | + | x | ) | + | x | ( | 29 | + | x | ) | − | 638 |
| = | 22 | × | 29 | + | 22 | x | + | x | ( | 29 | + | x | ) | − | 638 |
| = | 638 | + | 22 | x | + | x | ( | 29 | + | x | ) | − | 638 |
| = | 0 | + | 22 | x | + | x | ( | 29 | + | x | ) |
| = | 0 | + | 22 | x | + | x | × | 29 | + | x | x |
| = | 0 | + | 51 | x | + | x | x |
| 0 | + | 51 | x | + | x | x | = | 22 | × | 29 | ÷ | 4 |
| Right side of the equation = | 319 2 |
| 0 | + | 51 | x | + | x | x | = | 319 2 |