| 3 | ( | 13 | ( | 2 | ( | x | − | 15 | ) | + | 3 | ) | + | 14 | ) | − | 8 | ( | x | − | 4 | ) | = | 71 |
| Left side of the equation = | 3 | × | 13 | ( | 2 | ( | x | − | 15 | ) | + | 3 | ) | + | 3 | × | 14 | − | 8 | ( | x | − | 4 | ) |
| = | 39 | ( | 2 | ( | x | − | 15 | ) | + | 3 | ) | + | 42 | − | 8 | ( | x | − | 4 | ) |
| = | 39 | × | 2 | ( | x | − | 15 | ) | + | 39 | × | 3 | + | 42 | − | 8 | ( | x | − | 4 | ) |
| = | 78 | ( | x | − | 15 | ) | + | 117 | + | 42 | − | 8 | ( | x | − | 4 | ) |
| = | 78 | ( | x | − | 15 | ) | + | 159 | − | 8 | ( | x | − | 4 | ) |
| = | 78 | x | − | 78 | × | 15 | + | 159 | − | 8 | ( | x | − | 4 | ) |
| = | 78 | x | − | 1170 | + | 159 | − | 8 | ( | x | − | 4 | ) |
| = | 78 | x | − | 1011 | − | 8 | ( | x | − | 4 | ) |
| = | 78 | x | − | 1011 | − | 8 | x | + | 8 | × | 4 |
| = | 78 | x | − | 1011 | − | 8 | x | + | 32 |
| = | 70 | x | − | 979 |
| 70 | x | − | 979 | = | 71 |
| 70 | x | = | 71 | + | 979 |
| 70 | x | = | 1050 |
| x | = | 1050 | ÷ | 70 |
| = | 1050 | × | 1 70 |
| = | 15 | × | 1 |
| x | = | 15 |