| ( | 1 4 | − | n | ) | ( | 3 20 | − | n | ) | ÷ | ( | 1 20 | + | n | ) | = | 0 |
| 方程两边同时乘以: | ( | 1 20 | + | n | ) |
| ( | 1 4 | − | n | ) | ( | 3 20 | − | n | ) | = | 0 |
1 4 | ( | 3 20 | − | n | ) | − | n | ( | 3 20 | − | n | ) | = | 0 |
1 4 | × | 3 20 | − | 1 4 | n | − | n | ( | 3 20 | − | n | ) | = | 0 |
3 80 | − | 1 4 | n | − | n | ( | 3 20 | − | n | ) | = | 0 |
3 80 | − | 1 4 | n | − | n | × | 3 20 | + | n | n | = | 0 |
3 80 | − | 2 5 | n | + | n | n | = | 0 |
| n1= | 3 20 |
| n2= | 1 4 |