Solution
= Solution
If $\lambda=0$, then $Av=0$ for a nonzero <eigenvector> $v$, contradicting the existence of a <matrix inverse>. Hence $\lambda\ne0$. Multiplying $Av=\lambda v$ by $A^{-1}$ gives $v=\lambda A^{-1}v$, so
$$
\boxed{A^{-1}v=\lambda^{-1}v,\qquad \lambda^{-1}\text{ is an eigenvalue of }A^{-1}.}
$$