| ( | 660 | − | 480 | − | x | ) | ( | 480 | + | 10 | x | ) | + | ( | 520 | − | 380 | − | x | ) | ( | 380 | + | 15 | x | ) | = | 184400 |
| 方程左边 = | 660 | ( | 480 | + | 10 | x | ) | − | 480 | ( | 480 | + | 10 | x | ) | − | x | ( | 480 | + | 10 | x | ) | + | ( | 520 | − | 380 | − | x | ) | ( | 380 | + | 15 | x | ) |
| = | 660 | × | 480 | + | 660 | × | 10 | x | − | 480 | ( | 480 | + | 10 | x | ) | − | x | ( | 480 | + | 10 | x | ) | + | ( | 520 | − | 380 | − | x | ) | ( | 380 | + | 15 | x | ) |
| = | 316800 | + | 6600 | x | − | 480 | ( | 480 | + | 10 | x | ) | − | x | ( | 480 | + | 10 | x | ) | + | ( | 520 | − | 380 | − | x | ) | ( | 380 | + | 15 | x | ) |
| = | 316800 | + | 6600 | x | − | 480 | × | 480 | − | 480 | × | 10 | x | − | x | ( | 480 | + | 10 | x | ) | + | ( | 520 | − | 380 | − | x | ) | ( | 380 | + | 15 | x | ) |
| = | 316800 | + | 6600 | x | − | 230400 | − | 4800 | x | − | x | ( | 480 | + | 10 | x | ) | + | ( | 520 | − | 380 | − | x | ) | ( | 380 | + | 15 | x | ) |
| = | 86400 | + | 1800 | x | − | x | ( | 480 | + | 10 | x | ) | + | ( | 520 | − | 380 | − | x | ) | ( | 380 | + | 15 | x | ) |
| = | 86400 | + | 1800 | x | − | x | × | 480 | − | x | × | 10 | x | + | ( | 520 | − | 380 | − | x | ) | ( | 380 | + | 15 | x | ) |
| = | 86400 | + | 1320 | x | − | x | × | 10 | x | + | ( | 520 | − | 380 | − | x | ) | ( | 380 | + | 15 | x | ) |
| = | 86400 | + | 1320 | x | − | x | × | 10 | x | + | 520 | ( | 380 | + | 15 | x | ) | − | 380 | ( | 380 | + | 15 | x | ) | − | x | ( | 380 | + | 15 | x | ) |
| = | 86400 | + | 1320 | x | − | x | × | 10 | x | + | 520 | × | 380 | + | 520 | × | 15 | x | − | 380 |
| = | 86400 | + | 1320 | x | − | x | × | 10 | x | + | 197600 | + | 7800 | x | − | 380 | ( | 380 | + | 15 | x | ) | − | x |
| = | 284000 | + | 9120 | x | − | x | × | 10 | x | − | 380 | ( | 380 | + | 15 | x | ) | − | x | ( | 380 | + | 15 | x | ) |
| = | 284000 | + | 9120 | x | − | x | × | 10 | x | − | 380 | × | 380 | − | 380 | × | 15 | x | − | x |
| = | 284000 | + | 9120 | x | − | x | × | 10 | x | − | 144400 | − | 5700 | x | − | x | ( | 380 | + | 15 | x | ) |
| = | 139600 | + | 3420 | x | − | x | × | 10 | x | − | x | ( | 380 | + | 15 | x | ) |
| = | 139600 | + | 3420 | x | − | x | × | 10 | x | − | x | × | 380 | − | x | × | 15 | x |
| = | 139600 | + | 3040 | x | − | x | × | 10 | x | − | x | × | 15 | x |
| 139600 | + | 3040 | x | − | x | × | 10 | x | − | x | × | 15 | x | = | 184400 |