Notice the difference of two squares in the denominator?.
Now, see it?. You got a hole at x=3
"Find the x-values(if any) at which f is not continuous. Which of the discontinuites are removable?"
the funtion is f(x)=x-3/x^2-9
Ok so I know its discontinuous at 3. But is it removable or non removable? and why? Do you need to know the graph to determine this? Thanks.