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Interpret quadratic models


Amir throws a stone off of a bridge into a river. The stone's height (in meters above the water) t seconds after Amir throws it is modeled by
h, left parenthesis, t, right parenthesis, equals, minus, 5, t, squared, plus, 20, t, plus, 160
Amir wants to know when the stone will reach its highest point.
1) Rewrite the function in a different form (factored or vertex) where the answer appears as a number in the equation.
h, left parenthesis, t, right parenthesis, equals
2) How many seconds after being thrown did the stone reach its highest point?
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3, slash, 5
  • a simplified improper fraction, like 7, slash, 4
  • a mixed number, like 1, space, 3, slash, 4
  • an exact decimal, like 0, point, 75
  • a multiple of pi, like 12, space, start text, p, i, end text or 2, slash, 3, space, start text, p, i, end text