Why is this matrix invertible? I'm following Intro to stochastic processes by Lawler, page 27. 
It says if we have a matrix Q such that $Q^n \rightarrow0$, then the eigenvalues of Q have absolute value less than $1$. That part I understand.
Then it says: "Hence, $I-Q$ is invertible." How does that follow?
P.S. I understand the conditions for invertibility, like det can't be zero etc.

Hint: If $Q$ has no eigenvalue of $1$ then $I - Q$ has no eigenvalue of $0$.
