( | 10 | + | x | ) | x | ( | 150 | − | 10 | x | ) | = | 1560 |
方程左边 = | 10 | x | ( | 150 | − | 10 | x | ) | + | x | x | ( | 150 | − | 10 | x | ) |
= | 10 | x | × | 150 | − | 10 | x | × | 10 | x | + | x | x | ( | 150 | − | 10 | x | ) |
= | 1500 | x | − | 100 | x | x | + | x | x | ( | 150 | − | 10 | x | ) |
= | 1500 | x | − | 100 | x | x | + | x | x | × | 150 | − | x | x | × | 10 | x |
1500 | x | − | 100 | x | x | + | x | x | × | 150 | − | x | x | × | 10 | x | = | 1560 |