| ( | 90 | + | X | ) | + | 5 | = | ( | 180 | − | X | ) | × | 4 | ÷ | 9 |
| Left side of the equation = | 90 | + | X | + | 5 |
| = | 95 | + | X |
| 95 | + | X | = | ( | 180 | − | X | ) | × | 4 | ÷ | 9 |
| Right side of the equation = | ( | 180 | − | X | ) | × | 4 9 |
| 95 | + | X | = | ( | 180 | − | X | ) | × | 4 9 |
| Right side of the equation = | 180 | × | 4 9 | − | X | × | 4 9 |
| = | 80 | − | X | × | 4 9 |
| 95 | + | X | = | 80 | − | 4 9 | X |
| X | + | 4 9 | X | = | 80 | − | 95 |
13 9 | X | = | 80 | − | 95 |
13 9 | X | = | - | 15 |
| X | = | - | 15 | ÷ | 13 9 |
| = | - | 15 | × | 9 13 |
| X | = | - | 135 13 |
| X | = | - 10.384615 |