| ( | 3 5 | − | x | ) | ( | 500 | + | 1000 | x | ) | = | 240 |
| Left side of the equation = | 3 5 | ( | 500 | + | 1000 | x | ) | − | x | ( | 500 | + | 1000 | x | ) |
| = | 3 5 | × | 500 | + | 3 5 | × | 1000 | x | − | x | ( | 500 | + | 1000 | x | ) |
| = | 300 | + | 600 | x | − | x | ( | 500 | + | 1000 | x | ) |
| = | 300 | + | 600 | x | − | x | × | 500 | − | x | × | 1000 | x |
| = | 300 | + | 100 | x | − | x | × | 1000 | x |
| 300 | + | 100 | x | − | x | × | 1000 | x | = | 240 |
| x1= | - | 1 5 |
| x2= | 3 10 |