Determine all numbers at which the function is continuous

Answer
Please see attached image for full understanding of the solution
If we plot the function we can see that it has a discontinuity at x = 1.
Also,
If we evaluate at x = -9, we see that the values of the piecewise function in both cases are completely different.
Therefore, x = -9 is also a discontinuity.
The right answer is option a
(discontinuity at x = 1 and x = -9)