40 | ÷ | ( | x | − | 40 | ) | = | ( | x | + | 15 | ) | ÷ | ( | 2 | x | − | 15 | ) |
方程两边同时乘以: | ( | x | − | 40 | ) | , | ( | 2 | x | − | 15 | ) |
40 | ( | 2 | x | − | 15 | ) | = | ( | x | + | 15 | ) | ( | x | − | 40 | ) |
40 | × | 2 | x | − | 40 | × | 15 | = | ( | x | + | 15 | ) | ( | x | − | 40 | ) |
40 | × | 2 | x | − | 40 | × | 15 | = | x | ( | x | − | 40 | ) | + | 15 | ( | x | − | 40 | ) |
80 | x | − | 600 | = | x | ( | x | − | 40 | ) | + | 15 | ( | x | − | 40 | ) |
80 | x | − | 600 | = | x | x | − | x | × | 40 | + | 15 | ( | x | − | 40 | ) |
80 | x | − | 600 | = | x | x | − | 40 | x | + | 15 | x | − | 15 | × | 40 |
80 | x | − | 600 | = | x | x | − | 40 | x | + | 15 | x | − | 600 |
80 | x | − | 600 | = | x | x | − | 25 | x | − | 600 |
x2=105 |