| 103 | n | + | 13 | n | ( | n | − | 1 | ) | ÷ | 2 | = | 1125 |
| Left side of the equation = | 103 | n | + | 13 2 | n | ( | n | − | 1 | ) |
| 103 | n | + | 13 2 | n | ( | n | − | 1 | ) | = | 1125 |
| Left side of the equation = | 103 | n | + | 13 2 | n | n | − | 13 2 | n | × | 1 |
| = | 103 | n | + | 13 2 | n | n | − | 13 2 | n |
| = | 193 2 | n | + | 13 2 | n | n |
193 2 | n | + | 13 2 | n | n | = | 1125 |