Explanation:
Set the denominator equal to zero and solve for x. These are the asymptotes: x = -3 and x = 1
Notice that (x+3) cancels out from the numerator and denominator
This becomes a Removable Discontinuity, instead of an asymptote.
⇒ Therefore, x = 1 is the vertical asymptote
x = -3 is a removable discontinuity