( | 360 | − | 2 | x | ) | ( | 265 | − | 2 | x | ) | = | 72000 |
方程左边 = | 360 | ( | 265 | − | 2 | x | ) | − | 2 | x | ( | 265 | − | 2 | x | ) |
= | 360 | × | 265 | − | 360 | × | 2 | x | − | 2 | x | ( | 265 | − | 2 | x | ) |
= | 95400 | − | 720 | x | − | 2 | x | ( | 265 | − | 2 | x | ) |
= | 95400 | − | 720 | x | − | 2 | x | × | 265 | + | 2 | x | × | 2 | x |
= | 95400 | − | 720 | x | − | 530 | x | + | 4 | x | x |
= | 95400 | − | 1250 | x | + | 4 | x | x |
95400 | − | 1250 | x | + | 4 | x | x | = | 72000 |