A water rocket is launched froni a platform. The height, h in metres, of the water rocket at time & seconds after it is launch

Question

A water rocket is launched froni a platform. The height,
h in metres, of the water rocket at time & seconds after
it is launched is h= -212 + 74 + 4. When does the water
rocket hit the ground?​

in progress 0
MichaelMet 5 years 2021-08-28T18:52:23+00:00 1 Answers 35 views 0

Answers ( )

  1. Neala
    0
    2021-08-28T18:53:58+00:00
    Reply

    Answer:

    4.41seconds later

    Step-by-step explanation:

    Let the equation of the height reached by the water front be h = -2t^2+7t+4

    The water hits the ground at h =0

    Substitute

    0 =  -2t^2+7t+4

    -2t^2+7t+4 = 0

    2t^2 – 7t – 8 = 0

    t = 7±√(-7)²-4(2)(-8)/2(2)

    t = 7±√49+64/4

    t = 7±√113/4

    t = 7±10.63/4

    t = 7+10.63/4

    t = 17.3/4

    t = 4.41s

    Hence the water hit the ground 4.41seconda later

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Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )