| ( | 2 | − | x | ) | ( | 300 | + | 200 | x | ) | = | 0 |
| Left side of the equation = | 2 | ( | 300 | + | 200 | x | ) | − | x | ( | 300 | + | 200 | x | ) |
| = | 2 | × | 300 | + | 2 | × | 200 | x | − | x | ( | 300 | + | 200 | x | ) |
| = | 600 | + | 400 | x | − | x | ( | 300 | + | 200 | x | ) |
| = | 600 | + | 400 | x | − | x | × | 300 | − | x | × | 200 | x |
| = | 600 | + | 100 | x | − | x | × | 200 | x |
| 600 | + | 100 | x | − | x | × | 200 | x | = | 0 |
| x1= | - | 3 2 |
| x2=2 |