text: import numpy as np
  import math
  from scipy.stats.stats import pearsonr
  
  #ax+by=c
  #px+qy=r
  A = np.array([[8,-10],[40,-18]])
  B = np.array([-66,214])
  X = np.linalg.solve(A,B)
  
  mean_x = X[0]
  mean_y = X[1]
  
  print("mean_x : ",mean_x)
  print("mean_y : ",mean_y)
  
  # Equations : (x - x_mean) = bxy(y - y_mean) , (y - y_mean) = byx(x - x_mean)
  
  # case : 1 => 8x = 10y - 66 , 18y = 40x + 214
  bxy = 10/8
  byx = 40/18
  r = math.sqrt(bxy*byx)
  print("case 1 : ",r)
  
  # case : 2 => 10y = 8x + 66 , 40x = 18y - 214
  bxy = 18/40
  byx = 8/10
  r = math.sqrt(bxy*byx)
  print("case 2 : ",r)
  
  # selecting r such a way that r<=1 && r>=1
  # if byx and bxy are -ve then r is also -ve
  # for -ve numbers math.sqrt(-ve) gives "domain error" 