| ( | 18 | + | 27 | ) | x | + | 27 | ( | 1 | + | 1 | ÷ | 9 | ) | ( | 2 | x | − | 7 | − | x | ) | = | 540 |
| Left side of the equation = | 18 | x | + | 27 | x | + | 27 | ( | 1 | + | 1 | ÷ | 9 | ) | ( | 2 | x | − | 7 | − | x | ) |
| = | 45 | x | + | 27 | ( | 1 | + | 1 | ÷ | 9 | ) | ( | 2 | x | − | 7 | − | x | ) |
| = | 45 | x | + | 27 | × | 1 | ( | 2 | x | − | 7 | − | x | ) | + | 27 | × | 1 | ÷ | 9 | × | ( | 2 | x | − | 7 | − | x | ) |
| = | 45 | x | + | 27 | ( | 2 | x | − | 7 | − | x | ) | + | 3 | ( | 2 | x | − | 7 | − | x | ) |
| = | 45 | x | + | 27 | × | 2 | x | − | 27 | × | 7 | − | 27 | x | + | 3 | ( | 2 | x | − | 7 | − | x | ) |
| = | 45 | x | + | 54 | x | − | 189 | − | 27 | x | + | 3 | ( | 2 | x | − | 7 | − | x | ) |
| = | 72 | x | − | 189 | + | 3 | ( | 2 | x | − | 7 | − | x | ) |
| = | 72 | x | − | 189 | + | 3 | × | 2 | x | − | 3 | × | 7 | − | 3 | x |
| = | 72 | x | − | 189 | + | 6 | x | − | 21 | − | 3 | x |
| = | 75 | x | − | 210 |
| 75 | x | − | 210 | = | 540 |
| 75 | x | = | 540 | + | 210 |
| 75 | x | = | 750 |
| x | = | 750 | ÷ | 75 |
| = | 750 | × | 1 75 |
| = | 10 | × | 1 |
| x | = | 10 |