| x | = | 7800000 | ÷ | ( | ( | 40 | + | 10 | ) | × | 10 | ) |
| Multiply both sides of the equation by: | ( | ( | 40 | + | 10 | ) | × | 10 | ) |
| x | ( | ( | 40 | + | 10 | ) | × | 10 | ) | = | 7800000 |
| x | ( | 40 | + | 10 | ) | × | 10 | = | 7800000 |
| x | × | 40 | × | 10 | + | x | × | 10 | × | 10 | = | 7800000 |
| x | × | 400 | + | x | × | 100 | = | 7800000 |
| 500 | x | = | 7800000 |
| x | = | 7800000 | ÷ | 500 |
| = | 7800000 | × | 1 500 |
| = | 15600 | × | 1 |
| x | = | 15600 |