| 13 | + | ( | x | − | 3 | ) | x | × | 23 10 | − | ( | 8 | + | ( | x | − | 3 | ) | x | × | 2 | ) | = | 4 5 |
| Left side of the equation = | 13 | + | x | x | × | 23 10 | − | 3 | x | × | 23 10 | − | ( | 8 | + | ( | x | − | 3 | ) | x | × | 2 | ) |
| = | 13 | + | x | x | × | 23 10 | − | 69 10 | x | − | ( | 8 | + | ( | x | − | 3 | ) | x | × | 2 | ) |
| = | 13 | + | x | x | × | 23 10 | − | 69 10 | x | − | 8 | − | ( | x | − | 3 | ) | x | × | 2 |
| = | 5 | + | x | x | × | 23 10 | − | 69 10 | x | − | ( | x | − | 3 | ) | x | × | 2 |
| = | 5 | + | x | x | × | 23 10 | − | 69 10 | x | − | x | x | × | 2 | + | 3 | x | × | 2 |
| = | 5 | + | x | x | × | 23 10 | − | 69 10 | x | − | x | x | × | 2 | + | 6 | x |
| = | 5 | + | x | x | × | 23 10 | − | 9 10 | x | − | x | x | × | 2 |
| 5 | + | x | x | × | 23 10 | − | 9 10 | x | − | x | x | × | 2 | = | 4 5 |