Answer :
The function f(x) = 5x² + 40x is a parabola. Then the vertex of the parabola will be at (–4, –80).
What is the parabola?
It is the locus of a point that moves so that it is always the same distance from a non-movable point and a given line. The non-movable point is called focus and the non-movable line is called the directrix.
The function f(x) = 5x² + 40x
Then add and subtract 80, then we have
f(x) = 5x² + 40x + 80 – 80
f(x) = 5(x² + 8x + 16) – 80
f(x) = 5(x + 4)² – 80
The vertex of the parabola will be at (–4, –80).
More about the parabola link is given below.
https://brainly.com/question/8495504