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A ball is thrown from an initial height of 2 meters with an initial upward velocity of 20 m/s. The ball's height h (in meters) after t seconds is given by h=2+20t-5t^2. find all values of t for which the ball's height is 12 meters. Round your answers to the nearest tenth of a second.

Respuesta :

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2+20t-5t^2=12

5t^2-20t+10=0

t^2-4t+2=0  complete the square

t^2-4t=-2

t^2-4t+4=2  

(t-2)^2=2

t-2=±[tex] \sqrt{2} [/tex]

t=2±[tex] \sqrt{2} [/tex]

t≈(0.586, 3.41)

Answer:

t=0.27 or t=3.73

Step-by-step explanation:

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