4 | ( | ( | 2 | x | − | 9 | ) | ÷ | 3 | ) | ( | 15 | − | 2 | x | ) | = | 40 |
方程左边 = | 4 | ( | 2 | x | − | 9 | ) | ÷ | 3 | × | ( | 15 | − | 2 | x | ) |
= | 4 3 | ( | 2 | x | − | 9 | ) | ( | 15 | − | 2 | x | ) |
= | 4 3 | × | 2 | x | ( | 15 | − | 2 | x | ) | − | 4 3 | × | 9 | ( | 15 | − | 2 | x | ) |
= | 8 3 | x | ( | 15 | − | 2 | x | ) | − | 12 | ( | 15 | − | 2 | x | ) |
= | 8 3 | x | × | 15 | − | 8 3 | x | × | 2 | x | − | 12 | ( | 15 | − | 2 | x | ) |
= | 40 | x | − | 16 3 | x | x | − | 12 | ( | 15 | − | 2 | x | ) |
= | 40 | x | − | 16 3 | x | x | − | 12 | × | 15 | + | 12 | × | 2 | x |
= | 40 | x | − | 16 3 | x | x | − | 180 | + | 24 | x |
= | 64 | x | − | 16 3 | x | x | − | 180 |
64 | x | − | 16 3 | x | x | − | 180 | = | 40 |