Question

Check my answers?

Answer 1

What do you got?

Answer 2

A sandbag was thrown downward from a building. The function f(t) = -16t2 - 64t + 80 shows the height f(t), in feet, of the sandbag after t seconds:

Part A: Factor the function f(t) and use the factors to interpret the meaning of the x-intercept of the function.
Answer: Factoring f(t)=-16^2-64t+80 we get -16(t-1)(t+5)
f(t)=0 when t = -5 or t -1, this means the sandbox hits the ground after 1 second.

Part B: Complete the square of the expression for f(x) to determine the vertex of the graph of f(x). Would this be a maximum or minimum on the graph?
Answer:144-16(t+2)^2
The vertex is (-144,-2). It is a maximum.

Part C: Use your answer in part B to determine the axis of symmetry for f(x)?
Answer:Using part b we know the axis of symmetry is the line x =-2.

Answer 3

Those are my answers...

Answer 4

Your Part A: I believe you had a typo, should read f(t) = -5 or t = 1 (not -1

Answer 5

Right, thanks for catching that, what about the others?

Answer 6

Well when I complete the square for -16t^2 - 64t + 80, I divided thru by -16 getting:
t^2 + 4t -5 now to add a value to get a perfect square:
t^2 + 4t + 4 -5 = 4 simplifying
(t + 2)^2 = 9 taking the square root of both sides
t + 2 = 3, t = 1 How to apply this to be the vertex I don't believe I know what I am doing.

Answer 7

I don't guess I can be of too much further help. I gotta run now . time to eat.