SOLUTION: An Archer shoots an arrow. It's heights (in inches) at three times (in seconds) are given: Time is t Distance above ground is s at 3 seconds, the arrow was 326 ft above the

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Question 367386: An Archer shoots an arrow. It's heights (in inches) at three times (in seconds) are given:
Time is t
Distance above ground is s
at 3 seconds, the arrow was 326 ft above the ground
at 5 seconds, the arrow was 350 ft above the ground
at 8 seconds, the arrow was 146 ft above the ground
What is the maximum height of the arrow?
So far, all I have is s=-16t^2+140t+50, but I have no idea how to get the height of the arrow from there.
Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
the maximum value is the vertex of the parabola , which lies on the axis of symmetry

the general equation is ___ x = -b / (2a)

find x and then plug into your equation to find s