| 15 | ÷ | ( | 20 | + | x | ) | = | 15 | ÷ | ( | 15 | + | x | ) | − | 1 10 |
| Multiply both sides of the equation by: | ( | 20 | + | x | ) | , | ( | 15 | + | x | ) |
| 15 | ( | 15 | + | x | ) | = | 15 | ( | 20 | + | x | ) | − | 1 10 | ( | 20 | + | x | ) | ( | 15 | + | x | ) |
| 15 | × | 15 | + | 15 | x | = | 15 | ( | 20 | + | x | ) | − | 1 10 | ( | 20 | + | x | ) | ( | 15 | + | x | ) |
| 15 | × | 15 | + | 15 | x | = | 15 | × | 20 | + | 15 | x | − | 1 10 | ( | 20 | + | x | ) | ( | 15 | + | x | ) |
| 225 | + | 15 | x | = | 300 | + | 15 | x | − | 1 10 | ( | 20 | + | x | ) | ( | 15 | + | x | ) |
| 225 | + | 15 | x | = | 300 | + | 15 | x | − | 1 10 | × | 20 | ( | 15 | + | x | ) | − | 1 10 | x | ( | 15 | + | x | ) |
| 225 | + | 15 | x | = | 300 | + | 15 | x | − | 2 | ( | 15 | + | x | ) | − | 1 10 | x | ( | 15 | + | x | ) |
| 225 | + | 15 | x | = | 300 | + | 15 | x | − | 2 | × | 15 | − | 2 | x | − | 1 10 | x | ( | 15 | + | x | ) |
| 225 | + | 15 | x | = | 300 | + | 15 | x | − | 30 | − | 2 | x | − | 1 10 | x | ( | 15 | + | x | ) |
| 225 | + | 15 | x | = | 270 | + | 13 | x | − | 1 10 | x | ( | 15 | + | x | ) |
| 225 | + | 15 | x | = | 270 | + | 13 | x | − | 1 10 | x | × | 15 | − | 1 10 | x | x |
| 225 | + | 15 | x | = | 270 | + | 13 | x | − | 3 2 | x | − | 1 10 | x | x |
| 225 | + | 15 | x | = | 270 | + | 23 2 | x | − | 1 10 | x | x |