( | x | − | 40 | ) | ( | 500 | − | 10 | ( | x | − | 55 | ) | ) | = | 8000 |
方程左边 = | x | ( | 500 | − | 10 | ( | x | − | 55 | ) | ) | − | 40 | ( | 500 | − | 10 | ( | x | − | 55 | ) | ) |
= | x | × | 500 | − | x | × | 10 | ( | x | − | 55 | ) | − | 40 | ( | 500 | − | 10 | ( | x | − | 55 | ) | ) |
= | 500 | x | − | x | × | 10 | x | + | x | × | 10 | × | 55 | − | 40 | ( | 500 | − | 10 | ( | x | − | 55 | ) | ) |
= | 500 | x | − | x | × | 10 | x | + | x | × | 550 | − | 40 | ( | 500 | − | 10 | ( | x | − | 55 | ) | ) |
= | 1050 | x | − | x | × | 10 | x | − | 40 | ( | 500 | − | 10 | ( | x | − | 55 | ) | ) |
= | 1050 | x | − | x | × | 10 | x | − | 40 | × | 500 | + | 40 | × | 10 | ( | x | − | 55 | ) |
= | 1050 | x | − | x | × | 10 | x | − | 20000 | + | 400 | ( | x | − | 55 | ) |
= | 1050 | x | − | x | × | 10 | x | − | 20000 | + | 400 | x | − | 400 | × | 55 |
= | 1050 | x | − | x | × | 10 | x | − | 20000 | + | 400 | x | − | 22000 |
= | 1450 | x | − | x | × | 10 | x | − | 42000 |
1450 | x | − | x | × | 10 | x | − | 42000 | = | 8000 |