a performer shot from a cannon by h(x)= -2x^2+8x+10 where h(x) is the height of the performer and x is the seconds passed since cannon extremum of the function?

Question

what is the extremum of the function ? a. (-1,0) b. (0,10) c. (2,18) d. (5,0)

Answer 1

Being that you have a multiple choice question, you won't need to evaluate f(2).  Since the vertex is located at x=2, all you need to do is look for the point in your answer choice that contains a 2 as the x-coordinate. 

 

If you do have more than one answer choice that has a 2 as an x-coordinate, then you will need to evaluate f(2).

Answer 2

This function is a parabola. The extremum is at the vertex: x = -b/2a, or x = -8/2(-2), or x = 2

 

Knowing this you can determine the value of f(2).