| ( | x | ÷ | ( | 20 | ) | + | x | ÷ | ( | 30 | ) | ) | × | 4 | = | 10 |
| x | ÷ | ( | 20 | ) | × | 4 | + | x | ÷ | ( | 30 | ) | × | 4 | = | 10 |
| Multiply both sides of the equation by: | ( | 20 | ) |
| x | × | 4 | + | x | ÷ | ( | 30 | ) | × | 4 | ( | 20 | ) | = | 10 | ( | 20 | ) |
| x | × | 4 | + | x | ÷ | ( | 30 | ) | × | 4 | × | 20 | = | 10 | ( | 20 | ) |
| x | × | 4 | + | x | ÷ | ( | 30 | ) | × | 4 | × | 20 | = | 10 | × | 20 |
| x | × | 4 | + | x | ÷ | ( | 30 | ) | × | 80 | = | 200 |
| Multiply both sides of the equation by: | ( | 30 | ) |
| 4 | x | ( | 30 | ) | + | x | × | 80 | = | 200 | ( | 30 | ) |
| 4 | x | × | 30 | + | x | × | 80 | = | 200 | ( | 30 | ) |
| 4 | x | × | 30 | + | x | × | 80 | = | 200 | × | 30 |
| 120 | x | + | x | × | 80 | = | 6000 |
| 200 | x | = | 6000 |
| x | = | 6000 | ÷ | 200 |
| = | 6000 | × | 1 200 |
| = | 30 | × | 1 |
| x | = | 30 |