SOLUTION: Devonte throws a rock straight down off the edge of a cliff that overlooks the ocean. The distance (𝑑) the rock falls after 𝑑 seconds can be represented by the equation 𝑑

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Devonte throws a rock straight down off the edge of a cliff that overlooks the ocean. The distance (𝑑) the rock falls after 𝑑 seconds can be represented by the equation 𝑑       Log On


   

Question 1205748: Devonte throws a rock straight down off the edge of a cliff that overlooks the ocean. The distance (𝑑) the rock falls after 𝑑 seconds can be represented by the equation 𝑑 = 16𝑑² + 24𝑑. If the ocean’s surface is 16.4 feet below the cliff, to the nearest tenth, how many seconds will it take for the rock to hit the ocean’s surface?
Answer by ikleyn(52776) About Me  (Show Source):
You can put this solution on YOUR website!
.

This time "t" is the root of the equation

    h(t) = 0,

or

    16t^2 + 24t = 16.4

    16t^2 + 24t - 16.4 = 0.


Use the quadratic formula and take the positive root.