1. ## eigenvalues

find the characteristic polynomial of

A
, all the eigenvalues of A, and for each eigenvalue of A, find the set of all eigenvectors
of A with corresponding eigenvalue

A=.[4 3]
[-12 -9]

2. First solve
$\det \left[ \begin{array}{cc}4-\lambda &3\\-12&-9-\lambda \end{array} \right] =0$