| ( | 21 10 | + | 16 5 | ) | x | + | ( | 9 2 | + | 53 10 | ) | ( | 100 | − | x | ) | + | 180 | = | 0 |
| Left side of the equation = | 21 10 | x | + | 16 5 | x | + | ( | 9 2 | + | 53 10 | ) | ( | 100 | − | x | ) | + | 180 |
| = | 53 10 | x | + | ( | 9 2 | + | 53 10 | ) | ( | 100 | − | x | ) | + | 180 |
| = | 53 10 | x | + | 9 2 | ( | 100 | − | x | ) | + | 53 10 | ( | 100 | − | x | ) | + | 180 |
| = | 53 10 | x | + | 9 2 | × | 100 | − | 9 2 | x | + | 53 10 | ( | 100 | − | x | ) | + | 180 |
| = | 53 10 | x | + | 450 | − | 9 2 | x | + | 53 10 | ( | 100 | − | x | ) | + | 180 |
| = | 4 5 | x | + | 630 | + | 53 10 | ( | 100 | − | x | ) |
| = | 4 5 | x | + | 630 | + | 53 10 | × | 100 | − | 53 10 | x |
| = | 4 5 | x | + | 630 | + | 530 | − | 53 10 | x |
| = | - | 9 2 | x | + | 1160 |
| - | 9 2 | x | + | 1160 | = | 0 |
| - | 9 2 | x | = | 0 | − | 1160 |
| - | 9 2 | x | = | - | 1160 |
| 1160 | = | 9 2 | x |
9 2 | x | = | 1160 |
| x | = | 1160 | ÷ | 9 2 |
| = | 1160 | × | 2 9 |
| x | = | 2320 9 |
| x | = | 257.777778 |