SOLUTION: h=-4.9t^2+12t+45 the object is at a height of 45m. What amount of time will it take to hit the ground?

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Question 1040284: h=-4.9t^2+12t+45
the object is at a height of 45m. What amount of time will it take to hit the ground?
Answer by ikleyn(52780)   (Show Source):
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h = -4.9t^2+12t+45
the object is at a height of 45m. What amount of time will it take to hit the ground?
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It will hit the ground when h = 0.

To find t, solve this quadratic equation

= .

Use the quadratic formula (see the lessons
    - Introduction into Quadratic Equations
    - PROOF of quadratic formula by completing the square
in this site).

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