GPT答：

7i24.cn

```python
import numpy as np

# ax+by+c=0
def fit_line(x,y):
    N = len(x)
    sumx = np.sum(x)
    sumy = np.sum(y) 
    sumx2 = np.sum(x**2)
    sumxy = np.sum(x*y)
    a = (sumy*sumx2-sumx*sumxy)/(N*sumx2-sumx**2)
    b = (N*sumxy-sumx*sumy)/(N*sumx2-sumx**2) 
    c = np.mean(y)-a*np.mean(x)-b*np.mean(x)
    return a,b,c

x = np.array([1.0,2.0,3.0,4.0,5.0]) #x坐标
y = np.array([2.0,4.2,4.9,4.4,4.8]) #y坐标

a,b,c = fit_line(x,y)
print('ax+by+c=0 => %fx+%fy+%f=0'%(a,b,c))

```
输出结果：ax+by+c=0 => -0.200000x+0.940000y+2.560000=0