| 5 | ÷ | 6 | × | ( | x | − | 21 | ) | = | 4 | ÷ | 9 | × | x |
| Left side of the equation = | 5 6 | ( | x | − | 21 | ) |
5 6 | ( | x | − | 21 | ) | = | 4 | ÷ | 9 | × | x |
| Left side of the equation = | 5 6 | x | − | 5 6 | × | 21 |
| = | 5 6 | x | − | 35 2 |
5 6 | x | − | 35 2 | = | 4 | ÷ | 9 | × | x |
| Right side of the equation = | 4 9 | x |
5 6 | x | − | 35 2 | = | 4 9 | x |
5 6 | x | − | 4 9 | x | = | 35 2 |
7 18 | x | = | 35 2 |
| x | = | 35 2 | ÷ | 7 18 |
| = | 35 2 | × | 18 7 |
| = | 5 | × | 9 |
| x | = | 45 |