решение мариц python

from numpy import sqrt
from scipy.optimize import minimize
import numpy as np

A= np.array([[3.0, 1.0],[3.0,-1.0]])
B= np.array([2.0, 7.0, 9.0, -4.0])
#print np.linalg.det(A)



G=([[5.0, 1.0, -2.0, 1.0],[1.0, -1.0, 1.0, -1.0],[1.0, 1.0, 1.0, 1.0],[1.0, -2.0 ,-1.0, 1.0]])

a_1= np.linalg.inv(G)
#rint a_1

print np.dot( a_1, B)
print np.linalg.solve(G, B)