300 | ( | x | + | 1 | ) | ( | x | + | 1 | ) | = | 432 |
方程左边 = | 300 | x | ( | x | + | 1 | ) | + | 300 | × | 1 | ( | x | + | 1 | ) |
= | 300 | x | ( | x | + | 1 | ) | + | 300 | ( | x | + | 1 | ) |
= | 300 | x | x | + | 300 | x | × | 1 | + | 300 | ( | x | + | 1 | ) |
= | 300 | x | x | + | 300 | x | + | 300 | ( | x | + | 1 | ) |
= | 300 | x | x | + | 300 | x | + | 300 | x | + | 300 | × | 1 |
= | 300 | x | x | + | 300 | x | + | 300 | x | + | 300 |
= | 300 | x | x | + | 600 | x | + | 300 |
300 | x | x | + | 600 | x | + | 300 | = | 432 |
x1= | - | 11 5 |
x2= | 1 5 |