| 7 | ÷ | 9 | × | ( | 27 | − | 2 | x | ) | ( | 27 | − | 2 | x | ) | = | 21 | × | 27 | × | 3 | ÷ | 4 |
| Left side of the equation = | 7 9 | ( | 27 | − | 2 | x | ) | ( | 27 | − | 2 | x | ) |
7 9 | ( | 27 | − | 2 | x | ) | ( | 27 | − | 2 | x | ) | = | 21 | × | 27 | × | 3 | ÷ | 4 |
| Left side of the equation = | 7 9 | × | 27 | ( | 27 | − | 2 | x | ) | − | 7 9 | × | 2 | x | ( | 27 | − | 2 | x | ) |
| = | 21 | ( | 27 | − | 2 | x | ) | − | 14 9 | x | ( | 27 | − | 2 | x | ) |
| = | 21 | × | 27 | − | 21 | × | 2 | x | − | 14 9 | x | ( | 27 | − | 2 | x | ) |
| = | 567 | − | 42 | x | − | 14 9 | x | ( | 27 | − | 2 | x | ) |
| = | 567 | − | 42 | x | − | 14 9 | x | × | 27 | + | 14 9 | x | × | 2 | x |
| = | 567 | − | 42 | x | − | 42 | x | + | 28 9 | x | x |
| = | 567 | − | 84 | x | + | 28 9 | x | x |
| 567 | − | 84 | x | + | 28 9 | x | x | = | 21 | × | 27 | × | 3 | ÷ | 4 |
| Right side of the equation = | 1701 4 |
| 567 | − | 84 | x | + | 28 9 | x | x | = | 1701 4 |