| ( | 100 | − | x | ) | ÷ | 4 | = | 9 10 | x | ÷ | 54 | + | ( | 100 | − | ( | x | ÷ | 10 | + | 18 5 | x | ÷ | 54 | ) | ) | ÷ | 40 |
| Left side of the equation = | 100 | × | 1 4 | − | x | × | 1 4 |
| = | 25 | − | x | × | 1 4 |
| 25 | − | 1 4 | x | = | 9 10 | x | ÷ | 54 | + | ( | 100 | − | ( | x | ÷ | 10 | + | 18 5 | x | ÷ | 54 | ) | ) | ÷ | 40 |
| Right side of the equation = | 1 60 | x | + | ( | 100 | − | ( | x | ÷ | 10 | + | 18 5 | x | ÷ | 54 | ) | ) | × | 1 40 |
| 25 | − | 1 4 | x | = | 1 60 | x | + | ( | 100 | − | ( | x | ÷ | 10 | + | 18 5 | x | ÷ | 54 | ) | ) | × | 1 40 |
| Right side of the equation = | 1 60 | x | + | 100 | × | 1 40 | − | ( | x | ÷ | 10 | + | 18 5 | x | ÷ | 54 | ) | × | 1 40 |
| = | 1 60 | x | + | 5 2 | − | ( | x | ÷ | 10 | + | 18 5 | x | ÷ | 54 | ) | × | 1 40 |
| = | 1 60 | x | + | 5 2 | − | x | ÷ | 10 | × | 1 40 | − | 18 5 | x | ÷ | 54 | × | 1 40 |
| = | 1 60 | x | + | 5 2 | − | x | × | 1 400 | − | 1 600 | x |
| = | 1 80 | x | + | 5 2 |
| 25 | − | 1 4 | x | = | 1 80 | x | + | 5 2 |
| - | 1 4 | x | − | 1 80 | x | = | 5 2 | − | 25 |
| - | 21 80 | x | = | 5 2 | − | 25 |
| - | 21 80 | x | = | - | 45 2 |
45 2 | = | 21 80 | x |
21 80 | x | = | 45 2 |
| x | = | 45 2 | ÷ | 21 80 |
| = | 45 2 | × | 80 21 |
| = | 15 | × | 40 7 |
| x | = | 600 7 |
| x | = | 85.714286 |