| ( | 6500 | − | 13 10 | x | ) | ( | 3250 | − | 13 10 | x | ) | = | 0 |
| Left side of the equation = | 6500 | ( | 3250 | − | 13 10 | x | ) | − | 13 10 | x | ( | 3250 | − | 13 10 | x | ) |
| = | 6500 | × | 3250 | − | 6500 | × | 13 10 | x | − | 13 10 | x | ( | 3250 | − | 13 10 | x | ) |
| = | 21125000 | − | 8450 | x | − | 13 10 | x | ( | 3250 | − | 13 10 | x | ) |
| = | 21125000 | − | 8450 | x | − | 13 10 | x | × | 3250 | + | 13 10 | x | × | 13 10 | x |
| = | 21125000 | − | 8450 | x | − | 4225 | x | + | 169 100 | x | x |
| = | 21125000 | − | 12675 | x | + | 169 100 | x | x |
| 21125000 | − | 12675 | x | + | 169 100 | x | x | = | 0 |