| 24000 | = | ( | 500 | − | x | ) | ( | 40 | + | 1 5 | x | ) |
| Right side of the equation = | 500 | ( | 40 | + | 1 5 | x | ) | − | x | ( | 40 | + | 1 5 | x | ) |
| = | 500 | × | 40 | + | 500 | × | 1 5 | x | − | x | ( | 40 | + | 1 5 | x | ) |
| = | 20000 | + | 100 | x | − | x | ( | 40 | + | 1 5 | x | ) |
| = | 20000 | + | 100 | x | − | x | × | 40 | − | x | × | 1 5 | x |
| = | 20000 | + | 60 | x | − | x | × | 1 5 | x |
| 24000 | = | 20000 | + | 60 | x | − | x | × | 1 5 | x |