Answer:
NEITHER vertical stretching NOR vertical compression
Explanation:
f(x) = 1x^2-2x-15 = 1x^2 - 2x - 15
Because the coefficient of the x^2 term is 1, there is NEITHER vertical stretching NOR vertical compression.
Here f(x) = 1x^2 - 2x - 15 = x^2 - 2x + 1 - 1 - 15 = (x - 1)^2 - 16
represents a parabola whose vertex is at (1, -16), which opens up, and which has stretching in neither direction (horizontal or vertical).