| 5 | x | + | 37 10 | × | 21 | = | 21 5 | ( | 21 | + | x | ) |
| Left side of the equation = | 5 | x | + | 777 10 |
| 5 | x | + | 777 10 | = | 21 5 | ( | 21 | + | x | ) |
| Right side of the equation = | 21 5 | × | 21 | + | 21 5 | x |
| = | 441 5 | + | 21 5 | x |
| 5 | x | + | 777 10 | = | 441 5 | + | 21 5 | x |
| 5 | x | − | 21 5 | x | = | 441 5 | − | 777 10 |
4 5 | x | = | 441 5 | − | 777 10 |
4 5 | x | = | 21 2 |
| x | = | 21 2 | ÷ | 4 5 |
| = | 21 2 | × | 5 4 |
| x | = | 105 8 |
| x | = | 13.125 |