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Brainliest! Rock is thrown upward from top of 112-foot high cliff overlooking ocean at speed of 96 feet per second. The rocks height above can be modeled by
f(x)= -2t^2 + 92t - 480
Find the time t, in seconds when the rock would land in ocean

Respuesta :

mhanifa

Answer:

  • 40 seconds

Step-by-step explanation:

Find the value of t, when the value of f(x) is zero, assuming the ocean level is zero point.

Solve the equation:

  • -2t² + 92t - 480 = 0
  • t² - 46t + 240 = 0
  • t² - 40t - 6t + 240 = 0
  • t(t - 40) - 6(t - 40) = 0
  • (t - 6)(t - 40) = 0
  • t = 6, t = 40

The first root is not to be considered, as the rock was thrown from the positive height, not negative.

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