| ( | 2 | m | + | 7 | ) | ( | 2 | m | + | 2 | ) | = | 0 |
| Left side of the equation = | 2 | m | ( | 2 | m | + | 2 | ) | + | 7 | ( | 2 | m | + | 2 | ) |
| = | 2 | m | × | 2 | m | + | 2 | m | × | 2 | + | 7 | ( | 2 | m | + | 2 | ) |
| = | 4 | m | m | + | 4 | m | + | 7 | ( | 2 | m | + | 2 | ) |
| = | 4 | m | m | + | 4 | m | + | 7 | × | 2 | m | + | 7 | × | 2 |
| = | 4 | m | m | + | 4 | m | + | 14 | m | + | 14 |
| = | 4 | m | m | + | 18 | m | + | 14 |
| 4 | m | m | + | 18 | m | + | 14 | = | 0 |
| m1= | - | 7 2 |
| m2=-1 |