Given a specific Eigenvalue $\displaystyle \lambda$, how do I find an eigenvector of a Matrix $\displaystyle A$?

Specifically, if $\displaystyle \lambda = 4$ and $\displaystyle A =$ $\displaystyle \left[\begin{array}{rrr}3&0&-1\\2&3&1\\-3&4&5\end{array}\right]$

By the way, is there a way to make my Matrix look a little neater/lined up?