title: Inverse of a matrix 3x3 using symbols
body: <p>A have the following matrix, for example:</p>
  
  <p><img src="https://i.stack.imgur.com/QS0UJ.jpg" alt="enter image description here"></p>
  
  <p>And I want to do a few matrix operation without adding numbers as they may vary and I want to get general equations out of it.</p>
  
  <p>How can I get the inverse of something like that. If I want to do multiplication or simple operations seems to be fine, but nothing seems to work for the inverse.</p>
  
  <p>I've tried a lot like:</p>
  
  <pre><code>from sympy import *
  from numpy import matrix
  from numpy import linalg
  from sympy import Matrix
  
  a1, a2, a3, b1, b2, b3, c1, c2, c3, x, y, z = symbols('a1 a2 a3 b1 b2 b3 c1 c2 c3 x y z')
  A = matrix( [[a1,a2,a3],[b1,b2,b3],[c1,c2,c3]]) # Creates a matrix.
  B = matrix( [[x],[y],[z]])
  C= A*B  #That works fine
  A_inverse = A.inv() #Doesn't work
  </code></pre>