| 2 | ( | 1 | + | X | ) | ( | 1 | + | X | ) | = | 72 25 |
| Left side of the equation = | 2 | × | 1 | ( | 1 | + | X | ) | + | 2 | X | ( | 1 | + | X | ) |
| = | 2 | ( | 1 | + | X | ) | + | 2 | X | ( | 1 | + | X | ) |
| = | 2 | × | 1 | + | 2 | X | + | 2 | X | ( | 1 | + | X | ) |
| = | 2 | + | 2 | X | + | 2 | X | ( | 1 | + | X | ) |
| = | 2 | + | 2 | X | + | 2 | X | × | 1 | + | 2 | X | X |
| = | 2 | + | 2 | X | + | 2 | X | + | 2 | X | X |
| = | 2 | + | 4 | X | + | 2 | X | X |
| 2 | + | 4 | X | + | 2 | X | X | = | 72 25 |
| X1= | - | 11 5 |
| X2= | 1 5 |