A rocket is launched from a tower. The height of the rocket, y in feet, is related to the time after launch, x in seconds, by the given equation. Using this equation, find out
the time at which the rocket will reach its max, to the nearest 100th of a second.
y = -16x2 + 168x + 92

9514 1404 393

  5.25 seconds

Step-by-step explanation:

The vertex of the parabola defined by ax²+bx+c is located at x = -b/(2a).

The time to maximum altitude is ...

  x = -(168)/(2(-16)) = 168/32 = 5.25

The time at which maximum height is reached is 5.25 seconds after launch.

- 2 + 10x³ - 21x² + 19x - 4

step-by-step explanation:

each term in the second factor is multiplied by each term in the first factor

x²(- 2x² + 4x - 1) - 3x(- 2x² + 4x - 1) + 4(- 2x² + 4x - 1) ← distribute

= - 2 + 4x³ - x² + 6x³ - 12x² + 3x -8x² + 16x - 4

collect like terms

= - 2 + 10x³ - 21x² + 19x - 4 ← in standard form

109 is the nearest whole number/final answer! : )