Question

. Given the following function, f(x)=-x^2 -8x find:
(a) vertex, (b) axis of symmetry, (c) intercepts, (d) domain, (e) range,
(f) intervals where the function is increasing,
(g) intervals where the function is decreasing, and
(h) the graph of the function. Please show all of your work.
(Points : 15)

Answer 1

vertex: x = -b/2a = 8/-2 = -4, so y=-48: (-4,16)

axis: x = -4
x-intercepts: 0,-8
y-intercepts: 0
domain: all real x
range: all real y <= 16

y increasing where y' > 0
y' = -2x-8
y'>0 when x < -4
y decreasing for x > -4