90 | ( | 3 | − | x | ) | = | 45 | ( | 5 | − | x | ) |
方程左边 = | 90 | × | 3 | − | 90 | x |
= | 270 | − | 90 | x |
270 | − | 90 | x | = | 45 | ( | 5 | − | x | ) |
方程右边 = | 45 | × | 5 | − | 45 | x |
= | 225 | − | 45 | x |
270 | − | 90 | x | = | 225 | − | 45 | x |
- | 90 | x | + | 45 | x | = | 225 | − | 270 |
- | 45 | x | = | 225 | − | 270 |
- | 45 | x | = | - | 45 |
45 | = | 45 | x |
45 | x | = | 45 |
x | = | 45 | ÷ | 45 |
= | 45 | × | 1 45 |
= | 1 | × | 1 |
x | = | 1 |