The equation y = -16t^2 - 80t + 54 describes the height (in feet) of a ball thrown downward at 80 feet per second from a height of 54 feet from the ground, where t represents time, measured in seconds. In how many seconds will the ball hit the ground? Express your answer as a decimal rounded to the nearest hundredth.

Guest Jul 11, 2021

#1**+1 **

When the ball hits the ground, height = y will be ZERO

0 = - 16t^2 - 80t + 54 Use quadratic equation a = -16 b = -80 and c = 54 to solve for t

throe out the negative 't' value

\(t = {80 \pm \sqrt{(-80)^2-4(-16)(54)} \over 2(-16)}\)

You need to know how to calculate using the Quadratic Formula......if you already do, then here is a quick and easy Quadratic Formula calculator that I often use :

https://www.calculatorsoup.com/calculators/algebra/quadratic-formula-calculator.php

ElectricPavlov Jul 11, 2021