( | x | + | 1 | ) | ( | x | + | 2 | ) | = | ( | x | + | 3 | ) | ( | x | + | 4 | ) |
方程左边 = | x | ( | x | + | 2 | ) | + | 1 | ( | x | + | 2 | ) |
= | x | x | + | x | × | 2 | + | 1 | ( | x | + | 2 | ) |
= | x | x | + | 2 | x | + | 1 | x | + | 1 | × | 2 |
= | x | x | + | 2 | x | + | 1 | x | + | 2 |
= | x | x | + | 3 | x | + | 2 |
x | x | + | 3 | x | + | 2 | = | ( | x | + | 3 | ) | ( | x | + | 4 | ) |
方程右边 = | x | ( | x | + | 4 | ) | + | 3 | ( | x | + | 4 | ) |
= | x | x | + | x | × | 4 | + | 3 | ( | x | + | 4 | ) |
= | x | x | + | 4 | x | + | 3 | x | + | 3 | × | 4 |
= | x | x | + | 4 | x | + | 3 | x | + | 12 |
= | x | x | + | 7 | x | + | 12 |
x | x | + | 3 | x | + | 2 | = | x | x | + | 7 | x | + | 12 |
x= | - | 5 2 |