SOLUTION: A Ball is thrown from an inicial height of 3 feed Witherspoon an inicial upward velocidad of 30 ft/s.The ball's heght h (in feet ) after t esconde is giren by the following. h=3+3

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Question 1202327: A Ball is thrown from an inicial height of 3 feed Witherspoon an inicial upward velocidad of 30 ft/s.The ball's heght h (in feet ) after t esconde is giren by the following.
h=3+30t-16t^2
Find all values of t for which the ball's height is 11 feed.
Answer by math_tutor2020(3835) About Me  (Show Source):
You can put this solution on YOUR website!

Your post has strange typos.
I'm assuming it's supposed to be this:
A ball is thrown from an initial height of 3 feet with an initial upward velocity of 30 ft/s. The ball's height h (in feet) after t seconds is given by the following.
h = 3 + 30t - 16t^2
Find all values of t for which the ball's height is 11 feet.

If my assumption is incorrect, then please let me know.

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We want to find when the ball's height is 11 feet.
We want to find the value(s) of t which lead to h = 11.

h+=+3+%2B+30t+-+16t%5E2

11+=+3+%2B+30t+-+16t%5E2 Replace h with 11.

0+=+3+%2B+30t+-+16t%5E2-11

0+=+-16t%5E2+%2B+30t+-+8

-16t%5E2+%2B+30t+-+8+=+0

Then we turn to the quadratic formula.
Plugging in a = -16, b = 30, c = -8
t+=+%28-b+%2B-+sqrt%28b%5E2+-+4ac%29%29%2F%282a%29

t+=+%28-30+%2B-+sqrt%28%2830%29%5E2+-+4%28-16%29%28-8%29%29%29%2F%282%28-16%29%29

t+=+%28-30+%2B-+sqrt%28388%29%29%2F%28-32%29

t+=+%28-30+%2B+sqrt%28388%29%29%2F%28-32%29 or t+=+%28-30+-+sqrt%28388%29%29%2F%28-32%29

t+=+0.321946 or t+=+1.553054

Answers: Approximately t = 0.321946 and t = 1.553054