| ( | 10 | + | 2 | x | ) | ( | 700 | − | 15 | x | ) | − | 50 | x | = | 0 |
| Left side of the equation = | 10 | ( | 700 | − | 15 | x | ) | + | 2 | x | ( | 700 | − | 15 | x | ) | − | 50 | x |
| = | 10 | × | 700 | − | 10 | × | 15 | x | + | 2 | x | ( | 700 | − | 15 | x | ) | − | 50 | x |
| = | 7000 | − | 150 | x | + | 2 | x | ( | 700 | − | 15 | x | ) | − | 50 | x |
| = | 7000 | − | 200 | x | + | 2 | x | ( | 700 | − | 15 | x | ) |
| = | 7000 | − | 200 | x | + | 2 | x | × | 700 | − | 2 | x | × | 15 | x |
| = | 7000 | − | 200 | x | + | 1400 | x | − | 30 | x | x |
| = | 7000 | + | 1200 | x | − | 30 | x | x |
| 7000 | + | 1200 | x | − | 30 | x | x | = | 0 |