Please help me. I'm stuck on question C. I've tried 1 or -1 so please tell me what's wrong with that. Thank you.

Answer:
In the first two parts you have filled in the table and found the correct graph of the function y = x² - x - 2, which is C.
Now, to solve for part C, you need to consider y = 3 value on the graph C.
Corresponding points on x-axis are the points you are looking for.
The points are:
See the attached.