| X | + | ( | 4 5 | ( | X | − | 13 50 | ) | ) | = | 21 50 |
| Left side of the equation = | X | + | 4 5 | ( | X | − | 13 50 | ) |
| = | X | + | 4 5 | X | − | 4 5 | × | 13 50 |
| = | X | + | 4 5 | X | − | 26 125 |
| = | 9 5 | X | − | 26 125 |
9 5 | X | − | 26 125 | = | 21 50 |
9 5 | X | = | 21 50 | + | 26 125 |
9 5 | X | = | 157 250 |
| X | = | 157 250 | ÷ | 9 5 |
| = | 157 250 | × | 5 9 |
| = | 157 50 | × | 1 9 |
| X | = | 157 450 |
| X | = | 0.348889 |