| ( | 480 | − | x | ) | × | 2 | ( | 160 | − | 480 | + | x | ) | = | 20000 |
| Left side of the equation = | 480 | × | 2 | ( | 160 | − | 480 | + | x | ) | − | x | × | 2 | ( | 160 | − | 480 | + | x | ) |
| = | 960 | ( | 160 | − | 480 | + | x | ) | − | x | × | 2 | ( | 160 | − | 480 | + | x | ) |
| = | 960 | × | 160 | − | 960 | × | 480 | + | 960 | x | − | x | × | 2 | ( | 160 | − | 480 | + | x | ) |
| = | 153600 | − | 460800 | + | 960 | x | − | x | × | 2 | ( | 160 | − | 480 | + | x | ) |
| = | - | 307200 | + | 960 | x | − | x | × | 2 | ( | 160 | − | 480 | + | x | ) |
| = | - | 307200 | + | 960 | x | − | x | × | 2 | × | 160 | + | x | × | 2 | × | 480 | − | x | × | 2 | x |
| = | - | 307200 | + | 960 | x | − | x | × | 320 | + | x | × | 960 | − | x | × | 2 | x |
| = | - | 307200 | + | 1600 | x | − | x | × | 2 | x |
| - | 307200 | + | 1600 | x | − | x | × | 2 | x | = | 20000 |