import numpy as np
from scipy.linalg import solve


A = np.array(
    [
        [3.0, 1.0, -1.0],
        [2.0, 4.0, 1.0],
        [-1.0, 2.0, 5.0],
    ]
)
b = np.array([4.0, 1.0, 1.0])