MATH

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A toy rocket is launched vertically upward from ground level. This is represented as f(t) = -16t^2 + 128t where t is the time in second and f(t) is the height of the rocket in feet. When will the rocket hit the ground?

divide both sides by -16
0 = -16t^2 + 128t

0 = t^2 - 8t

0 = t(t-8t)

0 = t

0 = t-8

add 8 to both sides

8 = t

the rocket will hit the ground in 8 seconds.

can you tell me if I'm correct?

  • MATH -

    Yes, it is right.

  • MATH -

    no

  • MATH -

    what's wrong with it?

  • MATH -

    There's nothing wrong with it: it's correct.

  • MATH -

    Thanks!

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