| ( | 2 | t | − | 5 | ) | ( | 10 | − | t | ) | ÷ | 2 | = | 25 |
| Left side of the equation = | 2 | t | ( | 10 | − | t | ) | × | 1 2 | − | 5 | ( | 10 | − | t | ) | × | 1 2 |
| = | 1 | t | ( | 10 | − | t | ) | − | 5 2 | ( | 10 | − | t | ) |
| = | 1 | t | × | 10 | − | 1 | t | t | − | 5 2 | ( | 10 | − | t | ) |
| = | 10 | t | − | 1 | t | t | − | 5 2 | ( | 10 | − | t | ) |
| = | 10 | t | − | 1 | t | t | − | 5 2 | × | 10 | + | 5 2 | t |
| = | 10 | t | − | 1 | t | t | − | 25 | + | 5 2 | t |
| = | 25 2 | t | − | 1 | t | t | − | 25 |
25 2 | t | − | 1 | t | t | − | 25 | = | 25 |