| 200 | ( | 1 | + | a | ) | × | 9 | ÷ | 10 | × | 150 | ( | 1 | − | a | ) | = | 20000 |
| Left side of the equation = | 27000 | ( | 1 | + | a | ) | ( | 1 | − | a | ) |
| 27000 | ( | 1 | + | a | ) | ( | 1 | − | a | ) | = | 20000 |
| Left side of the equation = | 27000 | × | 1 | ( | 1 | − | a | ) | + | 27000 | a | ( | 1 | − | a | ) |
| = | 27000 | ( | 1 | − | a | ) | + | 27000 | a | ( | 1 | − | a | ) |
| = | 27000 | × | 1 | − | 27000 | a | + | 27000 | a | ( | 1 | − | a | ) |
| = | 27000 | − | 27000 | a | + | 27000 | a | ( | 1 | − | a | ) |
| = | 27000 | − | 27000 | a | + | 27000 | a | × | 1 | − | 27000 | a | a |
| = | 27000 | − | 27000 | a | + | 27000 | a | − | 27000 | a | a |
| = | 27000 | − | 0 | a | − | 27000 | a | a |
| 27000 | − | 0 | a | − | 27000 | a | a | = | 20000 |
| a1= | - | √70000 √27 |
| a2= | √70000 √27 |