120 | x | + | ( | 3 | x | − | 120 | ) | ( | ( | 1 | + | 1 | ÷ | 4 | ) | x | ) | = | 3 | − | 1 | ÷ | 5 |
方程左边 = | 120 | x | + | 3 | x | ( | ( | 1 | + | 1 | ÷ | 4 | ) | x | ) | − | 120 | ( | ( | 1 | + | 1 | ÷ | 4 | ) | x | ) |
= | 120 | x | + | 3 | x | ( | 1 | + | 1 | ÷ | 4 | ) | x | − | 120 | ( | ( | 1 | + | 1 | ÷ | 4 | ) | x | ) |
= | 120 | x | + | 3 | x | × | 1 | x | + | 3 | x | × | 1 | ÷ | 4 | × | x | − | 120 |
= | 120 | x | + | 3 | x | x | + | 3 4 | x | x | − | 120 | ( | ( | 1 | + | 1 | ÷ | 4 | ) | x | ) |
= | 120 | x | + | 3 | x | x | + | 3 4 | x | x | − | 120 | ( | 1 | + | 1 | ÷ | 4 | ) | x |
= | 120 | x | + | 3 | x | x | + | 3 4 | x | x | − | 120 | × | 1 | x | − | 120 |
= | 120 | x | + | 3 | x | x | + | 3 4 | x | x | − | 120 | x | − | 30 | x |
= | - | 30 | x | + | 3 | x | x | + | 3 4 | x | x |
- | 30 | x | + | 3 | x | x | + | 3 4 | x | x | = | 3 | − | 1 | ÷ | 5 |
方程右边 = | 3 | − | 1 5 |
= | 14 5 |
- | 30 | x | + | 3 | x | x | + | 3 4 | x | x | = | 14 5 |