| 4 | x | ( | 40 | − | 2 | x | ) | + | 2000 | x | = | 40000 | − | 200 | ( | 40 | − | 2 | x | ) |
| Left side of the equation = | 4 | x | × | 40 | − | 4 | x | × | 2 | x | + | 2000 | x |
| = | 160 | x | − | 8 | x | x | + | 2000 | x |
| = | 2160 | x | − | 8 | x | x |
| 2160 | x | − | 8 | x | x | = | 40000 | − | 200 | ( | 40 | − | 2 | x | ) |
| Right side of the equation = | 40000 | − | 200 | × | 40 | + | 200 | × | 2 | x |
| = | 40000 | − | 8000 | + | 400 | x |
| = | 32000 | + | 400 | x |
| 2160 | x | − | 8 | x | x | = | 32000 | + | 400 | x |