4 | ( | 9 | ÷ | 5 | ) | ( | 15 | − | 2 | x | ) | = | 40 |
方程左边 = | 4 | × | 9 | ÷ | 5 | × | ( | 15 | − | 2 | x | ) |
= | 36 5 | ( | 15 | − | 2 | x | ) |
= | 36 5 | × | 15 | − | 36 5 | × | 2 | x |
= | 108 | − | 72 5 | x |
108 | − | 72 5 | x | = | 40 |
- | 72 5 | x | = | 40 | − | 108 |
- | 72 5 | x | = | - | 68 |
68 | = | 72 5 | x |
72 5 | x | = | 68 |
x | = | 68 | ÷ | 72 5 |
= | 68 | × | 5 72 |
= | 17 | × | 5 18 |
x | = | 85 18 |
x | = | 4.722222 |