Need help with a math problem for ged practice test.?

SOMEONE ASKED 👇

Need help with a math problem for ged practice test.?

HERE THE ANSWERS 👇

• This was a tricky problem interpreting.

  h=-t^2+3t+10 where t is time in seconds and h is the height above a platform, so h=0 is when it “reaches the platform”.

  0 = -t^2+3t+10 now solve for t

  I would first reverse sides:

  t^2 -3t -10 = 0

  Factoring, Quadratic or completing the squares to solve.

  Factoring works:

  (t-5)(t+2) =0

  t=5 or t=-2

  Can throw away t=-2, negative time.

  t = 5 seconds

  ===

• h =-t^2 + 3t + 10

  Notice that this is an inverted parabola and that at t = 0, h = 10, (above platform)

  Since h is height above platform, it reaches platform when h = 0

  Multiply equation by – 1 and solve

  t^2 – 3t – 10 = (t + 2)(t – 5) = 0

  We are only concerned with time after t = 0, so select t = 5 as answer.

  After t = 0 the rocket has dropped from 10 computer units up, reaching platform at t = 5 secs.

  The result t = -2, h = 0 refers to a hypothetical position 2 seconds before t = 0,

  where the rocket would be if the parabolic curve was extended back before t = 0.

• t = 5

• h is the height above the platform. h=0 when the rocket reaches the platform. You have enough information.

  ___

  h = -(t -5)(t +2)

  The rocket will reach the platform 5 seconds after launch.