| ( | 20 | x | + | 10 | ( | 50 | − | x | ) | ) | × | 4 5 | = | 560 |
| Left side of the equation = | 20 | x | × | 4 5 | + | 10 | ( | 50 | − | x | ) | × | 4 5 |
| = | 16 | x | + | 8 | ( | 50 | − | x | ) |
| = | 16 | x | + | 8 | × | 50 | − | 8 | x |
| = | 16 | x | + | 400 | − | 8 | x |
| = | 8 | x | + | 400 |
| 8 | x | + | 400 | = | 560 |
| 8 | x | = | 560 | − | 400 |
| 8 | x | = | 160 |
| x | = | 160 | ÷ | 8 |
| = | 160 | × | 1 8 |
| = | 20 | × | 1 |
| x | = | 20 |