SOLUTION: Alice throws a ball to Connor. The height, h (in meters) after time, t (in
seconds) is approximated by the formula h= 2 + 28t – 5t^2. Calculate the time
required for the ball to
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Question 211092: Alice throws a ball to Connor. The height, h (in meters) after time, t (in
seconds) is approximated by the formula h= 2 + 28t – 5t^2. Calculate the time
required for the ball to reach a height of 15m.
Answer by algebrapro18(249) (Show Source): You can put this solution on YOUR website!
First you plug in the 15 into the equation which gives you 15 = 2 + 28t - 5t^2. Now all we have to do is solve for t. To start I suggest we get everything on the same side of the equation.
15 = 2 + 28t - 5t^2
15-2-28t+5t^2 = 2-2 + 28t-28t-5t^2+5t^2
13-28t+5t^2 = 0
Now lets just rearrange the equation so its in standard form.
5t^2-28t+13 = 0
Now try as we might this equation won't factor evenly so we have to use the quadratic equation.
where a = 5, b = -28, and c = 13. Plugging in those values gives us:
Now we just simplify:
Plugging this into our calculator we get answers of
t= 5.089104628 seconds or t = .510895 and I'm not sure which one we should use.
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