| ( | 50000 | − | 15 | x | ) | ( | 7 2 | x | + | 1140 | ) | = | 0 |
| Left side of the equation = | 50000 | ( | 7 2 | x | + | 1140 | ) | − | 15 | x | ( | 7 2 | x | + | 1140 | ) |
| = | 50000 | × | 7 2 | x | + | 50000 | × | 1140 | − | 15 | x | ( | 7 2 | x | + | 1140 | ) |
| = | 175000 | x | + | 57000000 | − | 15 | x | ( | 7 2 | x | + | 1140 | ) |
| = | 175000 | x | + | 57000000 | − | 15 | x | × | 7 2 | x | − | 15 | x | × | 1140 |
| = | 175000 | x | + | 57000000 | − | 105 2 | x | x | − | 17100 | x |
| = | 157900 | x | + | 57000000 | − | 105 2 | x | x |
| 157900 | x | + | 57000000 | − | 105 2 | x | x | = | 0 |