| ( | 6 | − | X | ) | ( | 6 | − | X | ) | + | 4 | X | X | + | ( | 12 | − | 2 | X | ) | ( | 12 | − | 2 | X | ) | + | X | X | + | 36 | = | X | X | + | 144 |
| Left side of the equation = | 6 | ( | 6 | − | X | ) | − | X | ( | 6 | − | X | ) | + | 4 | X | X | + | ( | 12 | − | 2 | X | ) | ( | 12 | − | 2 | X | ) | + | X | X | + | 36 |
| = | 6 | × | 6 | − | 6 | X | − | X | ( | 6 | − | X | ) | + | 4 | X | X | + | ( | 12 | − | 2 | X | ) | ( | 12 | − | 2 | X | ) | + | X |
| = | 36 | − | 6 | X | − | X | ( | 6 | − | X | ) | + | 4 | X | X | + | ( | 12 | − | 2 | X | ) | ( | 12 | − | 2 | X | ) | + | X | X |
| = | 72 | − | 6 | X | − | X | ( | 6 | − | X | ) | + | 4 | X | X | + | ( | 12 | − | 2 | X | ) | ( | 12 | − | 2 | X | ) | + | X | X |
| = | 72 | − | 6 | X | − | X | × | 6 | + | X | X | + | 4 | X | X | + | ( | 12 | − | 2 | X | ) | ( | 12 | − | 2 | X | ) |
| = | 72 | − | 12 | X | + | X | X | + | 4 | X | X | + | ( | 12 | − | 2 | X | ) | ( | 12 | − | 2 | X | ) | + | X | X |
| = | 72 | − | 12 | X | + | X | X | + | 4 | X | X | + | 12 | ( | 12 | − | 2 | X | ) | − | 2 | X |
| = | 72 | − | 12 | X | + | X | X | + | 4 | X | X | + | 12 | × | 12 | − | 12 | × | 2 |
| = | 72 | − | 12 | X | + | X | X | + | 4 | X | X | + | 144 | − | 24 | X | − | 2 |
| = | 216 | − | 36 | X | + | X | X | + | 4 | X | X | − | 2 | X | ( | 12 | − | 2 | X | ) | + | X |
| = | 216 | − | 36 | X | + | X | X | + | 4 | X | X | − | 2 | X | × | 12 | + | 2 |
| = | 216 | − | 36 | X | + | X | X | + | 4 | X | X | − | 24 | X | + | 4 | X |
| = | 216 | − | 60 | X | + | X | X | + | 4 | X | X | + | 4 | X | X | + | X |
| 216 | − | 60 | X | + | X | X | + | 4 | X | X | + | 4 | X | X | + | X | = | X | X | + | 144 |