SOLUTION: A ball is shot into the air. It's height , h in metres after t seconds is modeled by h=-4.9t^2 + 30t +1.6. How long to 2 decimal places will it take the ball to reach a height of 3

Question 210708: A ball is shot into the air. It's height , h in metres after t seconds is modeled by h=-4.9t^2 + 30t +1.6. How long to 2 decimal places will it take the ball to reach a height of 35m?
Answer by Earlsdon(6294) (Show Source): You can put this solution on YOUR website!
You need to find at what time, t, will the height, h, is equal to 35 metres.
Set h = 35 and solve for t.
Subtract 3 from both sides.
Solve this quadratic equation using the quadratic formula: In this equation, a = -4.9, b = 30, and c = -33.4. Make the appropriate substitutions into the formula:
Evaluate:

or
or Discard the negative solution
It will take 7.08 seconds for the ball to reach a height of 35 metres.
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