>>> B=np.array([[ 1,3,11],[7,9,17],[13,15,5]])
>>> 3*A-2*B
array([[  4,  -9, -13],
       [ -2, -24, -34],
       [-35, -21,   8]])
>>> -A
array([[-2,  1, -3],
       [-4,  2,  0],
       [ 3, -3, -6]])