| 40 | = | ( | 5 | + | 10 | ÷ | k | ) | ( | k | + | 2 | ) |
| 40 | = | 5 | ( | k | + | 2 | ) | + | 10 | ÷ | k | × | ( | k | + | 2 | ) |
| Multiply both sides of the equation by: | k |
| 40 | k | = | 5 | ( | k | + | 2 | ) | k | + | 10 | ( | k | + | 2 | ) |
| 40 | k | = | 5 | k | k | + | 5 | × | 2 | k | + | 10 | ( | k | + | 2 | ) |
| 40 | k | = | 5 | k | k | + | 10 | k | + | 10 | ( | k | + | 2 | ) |
| 40 | k | = | 5 | k | k | + | 10 | k | + | 10 | k | + | 10 | × | 2 |
| 40 | k | = | 5 | k | k | + | 10 | k | + | 10 | k | + | 20 |
| 40 | k | = | 5 | k | k | + | 20 | k | + | 20 |