| ( | 35 | − | 2 | X | ) | ( | 20 | − | 2 | X | ) | = | 400 |
| Left side of the equation = | 35 | ( | 20 | − | 2 | X | ) | − | 2 | X | ( | 20 | − | 2 | X | ) |
| = | 35 | × | 20 | − | 35 | × | 2 | X | − | 2 | X | ( | 20 | − | 2 | X | ) |
| = | 700 | − | 70 | X | − | 2 | X | ( | 20 | − | 2 | X | ) |
| = | 700 | − | 70 | X | − | 2 | X | × | 20 | + | 2 | X | × | 2 | X |
| = | 700 | − | 70 | X | − | 40 | X | + | 4 | X | X |
| = | 700 | − | 110 | X | + | 4 | X | X |
| 700 | − | 110 | X | + | 4 | X | X | = | 400 |