( | x | − | 20 | ) | ( | 50 | − | ( | x | − | 180 | ) | ) | = | 9450 |
方程左边 = | x | ( | 50 | − | ( | x | − | 180 | ) | ) | − | 20 | ( | 50 | − | ( | x | − | 180 | ) | ) |
= | x | × | 50 | − | x | ( | x | − | 180 | ) | − | 20 | ( | 50 | − | ( | x | − | 180 | ) | ) |
= | 50 | x | − | x | x | + | x | × | 180 | − | 20 | ( | 50 | − | ( | x | − | 180 | ) | ) |
= | 230 | x | − | x | x | − | 20 | ( | 50 | − | ( | x | − | 180 | ) | ) |
= | 230 | x | − | x | x | − | 20 | × | 50 | + | 20 | ( | x | − | 180 | ) |
= | 230 | x | − | x | x | − | 1000 | + | 20 | ( | x | − | 180 | ) |
= | 230 | x | − | x | x | − | 1000 | + | 20 | x | − | 20 | × | 180 |
= | 230 | x | − | x | x | − | 1000 | + | 20 | x | − | 3600 |
= | 250 | x | − | x | x | − | 4600 |
250 | x | − | x | x | − | 4600 | = | 9450 |