<|system|>
If $f (x) = x^2 - 1$, what is the value of $f (-1)$?</s>.
<|user|>
Can you answer based on context?
<|assistant|>
So if we plug in -1 for x, we get $(-1)^2 - 1$. Which is just 0. Right. So $f(-1) = 0$.

