| ( | 3400 | × | 9000 | + | 4500 | x | ) | ÷ | ( | 9000 | + | x | ) | = | 4000 |
| Multiply both sides of the equation by: | ( | 9000 | + | x | ) |
| ( | 3400 | × | 9000 | + | 4500 | x | ) | = | 4000 | ( | 9000 | + | x | ) |
| 3400 | × | 9000 | + | 4500 | x | = | 4000 | ( | 9000 | + | x | ) |
| 3400 | × | 9000 | + | 4500 | x | = | 4000 | × | 9000 | + | 4000 | x |
| 30600000 | + | 4500 | x | = | 36000000 | + | 4000 | x |
| 4500 | x | − | 4000 | x | = | 36000000 | − | 30600000 |
| 500 | x | = | 36000000 | − | 30600000 |
| 500 | x | = | 5400000 |
| x | = | 5400000 | ÷ | 500 |
| = | 5400000 | × | 1 500 |
| = | 10800 | × | 1 |
| x | = | 10800 |