import numpy as np
import matplotlib.pyplot as plt

def M(a,b,c) :
    return np.array([[a,b,c],[c,a,b],[b,c,a]])
    
print(np.dot(M(7,-14,1),M(1,2,3)))
print(np.dot(M(1,2,3),M(7,-14,1)))

def P(m,x) :
    return x**3-x**2+m
    
X = np.linspace(-1,1.5,100)
for m in [-0.1,0,0.1,0.2] :
    Y = [P(m,x) for x in X]
    plt.plot(X,Y)
plt.plot(X,[0 for x in X],'--',color='k')
plt.show()