| 12 | x | ÷ | 2 | + | 9 | x | + | ( | 9 | − | x | ) | × | 9 | ÷ | 2 | = | 11 | × | 9 | ÷ | 2 |
| Left side of the equation = | 6 | x | + | 9 | x | + | ( | 9 | − | x | ) | × | 9 2 |
| = | 15 | x | + | ( | 9 | − | x | ) | × | 9 2 |
| 15 | x | + | ( | 9 | − | x | ) | × | 9 2 | = | 11 | × | 9 | ÷ | 2 |
| Left side of the equation = | 15 | x | + | 9 | × | 9 2 | − | x | × | 9 2 |
| = | 15 | x | + | 81 2 | − | x | × | 9 2 |
| = | 21 2 | x | + | 81 2 |
21 2 | x | + | 81 2 | = | 11 | × | 9 | ÷ | 2 |
| Right side of the equation = | 99 2 |
21 2 | x | + | 81 2 | = | 99 2 |
21 2 | x | = | 99 2 | − | 81 2 |
21 2 | x | = | 9 |
| x | = | 9 | ÷ | 21 2 |
| = | 9 | × | 2 21 |
| = | 3 | × | 2 7 |
| x | = | 6 7 |
| x | = | 0.857143 |