| 1664 | ( | 1 | + | 5 | x | ) | ÷ | ( | 1200 | + | x | ) | = | 0 |
| Multiply both sides of the equation by: | ( | 1200 | + | x | ) |
| 1664 | ( | 1 | + | 5 | x | ) | = | 0 |
| 1664 | × | 1 | + | 1664 | × | 5 | x | = | 0 |
| 1664 | + | 8320 | x | = | 0 |
| 8320 | x | = | 0 | − | 1664 |
| 8320 | x | = | - | 1664 |
| x | = | - | 1664 | ÷ | 8320 |
| = | - | 1664 | × | 1 8320 |
| = | - | 1 | × | 1 5 |
| x | = | - | 1 5 |
| x | = | - 0.2 |