| ( | 1 | − | x | ) | ( | 200 | + | 4 | x | ) | − | 24 | = | 20 |
| Left side of the equation = | 1 | ( | 200 | + | 4 | x | ) | − | x | ( | 200 | + | 4 | x | ) | − | 24 |
| = | 1 | × | 200 | + | 1 | × | 4 | x | − | x | ( | 200 | + | 4 | x | ) | − | 24 |
| = | 200 | + | 4 | x | − | x | ( | 200 | + | 4 | x | ) | − | 24 |
| = | 176 | + | 4 | x | − | x | ( | 200 | + | 4 | x | ) |
| = | 176 | + | 4 | x | − | x | × | 200 | − | x | × | 4 | x |
| = | 176 | − | 196 | x | − | x | × | 4 | x |
| 176 | − | 196 | x | − | x | × | 4 | x | = | 20 |