| ( | 157 2 | − | Y | ) | ÷ | Y | = | 21 100 |
| Multiply both sides of the equation by: | Y |
| ( | 157 2 | − | Y | ) | = | 21 100 | Y |
157 2 | − | Y | = | 21 100 | Y |
| - | Y | − | 21 100 | Y | = | - | 157 2 |
| - | 121 100 | Y | = | - | 157 2 |
157 2 | = | 121 100 | Y |
121 100 | Y | = | 157 2 |
| Y | = | 157 2 | ÷ | 121 100 |
| = | 157 2 | × | 100 121 |
| = | 157 | × | 50 121 |
| Y | = | 7850 121 |
| Y | = | 64.876033 |