Question

Over what interval is the graph of f(x) = –(x + 8)2 – 1 decreasing?

(negative 8, infinity)
(8, infinity)
(negative infinity, 8)
(negative infinity, negative 8)

Answer 1

f(x) = −(x+8)^2 − 1 has vertex at x = −8 and opens downward, so it decreases for x > −8.

Answer: (−8, ∞)