( | 9 | x | + | 5 | ) | ( | 50 | − | 9 | x | ) | = | 736 |
方程左边 = | 9 | x | ( | 50 | − | 9 | x | ) | + | 5 | ( | 50 | − | 9 | x | ) |
= | 9 | x | × | 50 | − | 9 | x | × | 9 | x | + | 5 | ( | 50 | − | 9 | x | ) |
= | 450 | x | − | 81 | x | x | + | 5 | ( | 50 | − | 9 | x | ) |
= | 450 | x | − | 81 | x | x | + | 5 | × | 50 | − | 5 | × | 9 | x |
= | 450 | x | − | 81 | x | x | + | 250 | − | 45 | x |
= | 405 | x | − | 81 | x | x | + | 250 |
405 | x | − | 81 | x | x | + | 250 | = | 736 |