| ( | 120 | + | 2 | X | ) | ( | 80 | + | X | ) | = | 24080 |
| Left side of the equation = | 120 | ( | 80 | + | X | ) | + | 2 | X | ( | 80 | + | X | ) |
| = | 120 | × | 80 | + | 120 | X | + | 2 | X | ( | 80 | + | X | ) |
| = | 9600 | + | 120 | X | + | 2 | X | ( | 80 | + | X | ) |
| = | 9600 | + | 120 | X | + | 2 | X | × | 80 | + | 2 | X | X |
| = | 9600 | + | 120 | X | + | 160 | X | + | 2 | X | X |
| = | 9600 | + | 280 | X | + | 2 | X | X |
| 9600 | + | 280 | X | + | 2 | X | X | = | 24080 |