l=matrix([[1,0,0],[1,2,1],[0,1,2]]);
print l

a=l.inverse()
print a

b=matrix([[4],[5],[6]])
print b

c=a*b
print c

u=matrix([[1,1,1],[0,1,1],[0,0,1]])
print u

e=u.inverse()
print e

x=e*c
print x