Question

Let f(x)=18−7x−x^2. Find the open intervals on which f is increasing (decreasing).
1. f is increasing on the intervals
2. f is decreasing on the intervals

Answer 1

is this calculus class or algebra?

Answer 2

if it is algebra, then find the first coordinate of the vertex
actually if it is calculus, do the same thing

Answer 3

vertex is \(-\frac{b}{2a}\) which is your case is \(-\frac{-7}{2(-1)}=-\frac{7}{2}\)

Answer 4

its for calculus

Answer 5

ok well it makes no difference
this is a parabola that opens down. it is increasing on \((-\infty, -\frac{7}{2})\) and decreasing elsewhere

Answer 6

okay thank you