( | 7 | − | x | ) | ÷ | 2 | + | x | + | x | + | 1 | = | 9 |
方程左边 = | ( | 7 | − | x | ) | × | 1 2 | + | 2 | x | + | 1 |
( | 7 | − | x | ) | × | 1 2 | + | 2 | x | + | 1 | = | 9 |
方程左边 = | 7 | × | 1 2 | − | x | × | 1 2 | + | 2 | x | + | 1 |
= | 7 2 | − | x | × | 1 2 | + | 2 | x | + | 1 |
= | 9 2 | + | 3 2 | x |
9 2 | + | 3 2 | x | = | 9 |
3 2 | x | = | 9 | − | 9 2 |
3 2 | x | = | 9 2 |
x | = | 9 2 | ÷ | 3 2 |
= | 9 2 | × | 2 3 |
= | 3 | × | 1 |
x | = | 3 |