( | - | 4 | x | + | 280 | ) | ( | 80 | − | 4 | x | ) | + | ( | 4 | x | + | 120 | ) | ( | 4 | x | + | 8 | ) | = | 17280 |
方程左边 = | - | 4 | x | ( | 80 | − | 4 | x | ) | + | 280 | ( | 80 | − | 4 | x | ) | + | ( | 4 | x | + | 120 | ) | ( | 4 | x | + | 8 | ) |
= | - | 4 | x | × | 80 | + | 4 | x | × | 4 | x | + | 280 | ( | 80 | − | 4 | x | ) | + | ( | 4 | x | + | 120 | ) | ( | 4 | x | + | 8 | ) |
= | - | 320 | x | + | 16 | x | x | + | 280 | ( | 80 | − | 4 | x | ) | + | ( | 4 | x | + | 120 | ) | ( | 4 | x | + | 8 | ) |
= | - | 320 | x | + | 16 | x | x | + | 280 | × | 80 | − | 280 | × | 4 | x | + | ( | 4 | x | + | 120 | ) | ( | 4 | x | + | 8 | ) |
= | - | 320 | x | + | 16 | x | x | + | 22400 | − | 1120 | x | + | ( | 4 | x | + | 120 | ) | ( | 4 | x | + | 8 | ) |
= | - | 1440 | x | + | 16 | x | x | + | 22400 | + | ( | 4 | x | + | 120 | ) | ( | 4 | x | + | 8 | ) |
= | - | 1440 | x | + | 16 | x | x | + | 22400 | + | 4 | x | ( | 4 | x | + | 8 | ) | + | 120 | ( | 4 | x | + | 8 | ) |
= | - | 1440 | x | + | 16 | x | x | + | 22400 | + | 4 | x | × | 4 | x | + | 4 | x |
= | - | 1440 | x | + | 16 | x | x | + | 22400 | + | 16 | x | x | + | 32 | x | + | 120 |
= | - | 1408 | x | + | 16 | x | x | + | 22400 | + | 16 | x | x | + | 120 | ( | 4 | x | + | 8 | ) |
= | - | 1408 | x | + | 16 | x | x | + | 22400 | + | 16 | x | x | + | 120 | × | 4 | x |
= | - | 1408 | x | + | 16 | x | x | + | 22400 | + | 16 | x | x | + | 480 | x | + | 960 |
= | - | 928 | x | + | 16 | x | x | + | 23360 | + | 16 | x | x |
- | 928 | x | + | 16 | x | x | + | 23360 | + | 16 | x | x | = | 17280 |