| ( | s | + | 1 | ) | ( | s | + | 5 | ) | + | s | ( | s | + | 1 | ) | + | s | ( | s | + | 5 | ) | = | 0 |
| Left side of the equation = | s | ( | s | + | 5 | ) | + | 1 | ( | s | + | 5 | ) | + | s | ( | s | + | 1 | ) | + | s | ( | s | + | 5 | ) |
| = | s | s | + | s | × | 5 | + | 1 | ( | s | + | 5 | ) | + | s | ( | s | + | 1 | ) | + | s | ( | s | + | 5 | ) |
| = | s | s | + | 5 | s | + | 1 | s | + | 1 | × | 5 | + | s | ( | s | + | 1 | ) | + | s | ( | s | + | 5 | ) |
| = | s | s | + | 5 | s | + | 1 | s | + | 5 | + | s | ( | s | + | 1 | ) | + | s | ( | s | + | 5 | ) |
| = | s | s | + | 6 | s | + | 5 | + | s | ( | s | + | 1 | ) | + | s | ( | s | + | 5 | ) |
| = | s | s | + | 6 | s | + | 5 | + | s | s | + | s | × | 1 | + | s | ( | s | + | 5 | ) |
| = | s | s | + | 7 | s | + | 5 | + | s | s | + | s | ( | s | + | 5 | ) |
| = | s | s | + | 7 | s | + | 5 | + | s | s | + | s | s | + | s | × | 5 |
| = | s | s | + | 12 | s | + | 5 | + | s | s | + | s | s |
| s | s | + | 12 | s | + | 5 | + | s | s | + | s | s | = | 0 |