| ( | 498 | + | 215 | ) | ( | 498 | + | 215 | ) | = | 500 | × | 500 | + | ( | 498 | + | x | − | 20 | ) | ( | 498 | + | x | − | 20 | ) |
| Left side of the equation = | 498 | ( | 498 | + | 215 | ) | + | 215 | ( | 498 | + | 215 | ) |
| = | 498 | × | 498 | + | 498 | × | 215 | + | 215 | ( | 498 | + | 215 | ) |
| = | 248004 | + | 107070 | + | 215 | ( | 498 | + | 215 | ) |
| = | 355074 | + | 215 | ( | 498 | + | 215 | ) |
| = | 355074 | + | 215 | × | 498 | + | 215 | × | 215 |
| = | 355074 | + | 107070 | + | 46225 |
| = | 508369 |
| 508369 | = | 500 | × | 500 | + | ( | 498 | + | x | − | 20 | ) | ( | 498 | + | x | − | 20 | ) |
| Right side of the equation = | 250000 | + | ( | 498 | + | x | − | 20 | ) | ( | 498 | + | x | − | 20 | ) |
| 508369 | = | 250000 | + | ( | 498 | + | x | − | 20 | ) | ( | 498 | + | x | − | 20 | ) |
| Right side of the equation = | 250000 | + | 498 | ( | 498 | + | x | − | 20 | ) | + | x | ( | 498 | + | x | − | 20 | ) | − | 20 | ( | 498 | + | x | − | 20 | ) |
| = | 250000 | + | 498 | × | 498 | + | 498 | x | − | 498 | × | 20 | + | x | ( | 498 | + | x | − | 20 | ) | − | 20 | ( | 498 | + | x | − | 20 | ) |
| = | 250000 | + | 248004 | + | 498 | x | − | 9960 | + | x | ( | 498 | + | x | − | 20 | ) | − | 20 | ( | 498 | + | x | − | 20 | ) |
| = | 488044 | + | 498 | x | + | x | ( | 498 | + | x | − | 20 | ) | − | 20 | ( | 498 | + | x | − | 20 | ) |
| = | 488044 | + | 498 | x | + | x | × | 498 | + | x | x | − | x | × | 20 | − | 20 | ( | 498 | + | x | − | 20 | ) |
| = | 488044 | + | 976 | x | + | x | x | − | 20 | ( | 498 | + | x | − | 20 | ) |
| = | 488044 | + | 976 | x | + | x | x | − | 20 | × | 498 | − | 20 | x | + | 20 | × | 20 |
| = | 488044 | + | 976 | x | + | x | x | − | 9960 | − | 20 | x | + | 400 |
| = | 478484 | + | 956 | x | + | x | x |
| 508369 | = | 478484 | + | 956 | x | + | x | x |