I don’t have the answer but, you and I have something in common with our profile pictures.
No, there can not be negative amplitude because it is just the distance between the max and the midline or the minimum and the midline.
I see where you might be confused because for instance in the trig equation:
y = -3 sin (.5(x-

/2)) -1, there is a negative in front of the amplitude. However, when finding the amplitude, you take the absolute value of a.
Answer:
x>-9
Step-by-step explanation:
Here's the steps (if you know how just do this equation as if it was a literal equation)