we know that
The equation in vertex form of a vertical parabola is equal to

where
(h,k) is the vertex of the parabola
and the axis of symmetry is equal to the x-coordinate of the vertex
so
-----> equation of the axis of symmetry
In this problem we have

Convert to vertex form
Group terms that contain the same variable, and move the constant to the opposite side of the equation


Complete the square. Remember to balance the equation by adding the same constants to each side


Rewrite as perfect squares
the vertex is the point 
therefore
<u>the answer is</u>
The axis of symmetry is

see the attached figure to better understand the problem
I got -2 as the slope hope this helps:)
Hey there!
Since there are 3 friends running an equal amount of this relay race, each will run 1/3 of the relay.
This is because 3 thirds make a whole, and each third is equal to the others, so if you add each distance ran by each of the friends, or simply multiply each portion by 3, you'd get 10 miles.
If you're also looking for how long each friend runs, which I know isn't in the question but I'll add it anyways, it is 3 1/3 miles. This can be found by dividing 10 into 3 equal parts.
Hope this helps!