Answer:
There is no manual shortcut except you're using a program like MATLAB or Mathcad.
Otherwise the process still remains the same:
1. Find the determinant |a|
2. Find the minor, then find the cofactors C
3. Find the adjoint of a which is the transpose of C
4. Find the inverse with
[tex] \frac{1}{ |a | } \: \times adjoint \: of \: a[/tex]
