So I have the matrix

$\displaystyle A=\left(\begin{matrix} 2/5 &1/5\\x &0\end{matrix}\right)$

And it asks me to find the eigenvalues (as expressions in the parameter x)

So using λ=Lambda I got: λ^2-(2/5)λ-(1/5)x. How am I supposed to factor that to find the eigenvalues when x is there?