Answer: 
.
Step-by-step explanation:
As we know ,
The slope of a line that passes through 
and 
is given by :
The slope of a line that passes through (1 , 7K), and (-3,5K) =
Hence, the slope of the given line is .
The function f(x) = 5x² + 40x is a parabola. Then the vertex of the parabola will be at (–4, –80).
<h3>What is the parabola?</h3>
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.
brainly.com/question/8495504
