SOLUTION: If someone could help me find the answer. I have been doing this problem over and over. A ball is thrown from an initial height of 2 meters with an initial upward velocity of 9 m

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Question 1145065: If someone could help me find the answer. I have been doing this problem over and over.
A ball is thrown from an initial height of 2 meters with an initial upward velocity of 9 m/s. The balls height “h” (in meters) after “t” seconds is given by the following.
H=2+9t-5t squared
Find all values of “t” for which the balls height is 4 meters.
Answer by greenestamps(13206) About Me  (Show Source):
You can put this solution on YOUR website!


What part of the problem do you need help with?

You are given a formula for the height h as a function of time t:

h+=+2%2B9t-5t%5E2

You are then given a height (4m) and asked to find the times t when the ball is that height:

4+=+2%2B9t-5t%5E2

That's a quadratic equation. Put it in standard form and solve by your favorite method.

5t%5E2-9t%2B2+=+0

That one will factor....

%285t-1%29%28t-2%29+=+0

Can you finish?

(If you weren't able to see that the quadratic was factorable, you can always solve any quadratic equation using the quadratic formula....)