Question 831087
#1. 
A person standing close to the edge on the top of a 122-foot building throws a baseball vertically upward. The quadratic equation

 h = -16 t^2 + 96 t + 122

models the ball's height  h   above the ground in feet, t seconds after it was thrown.

How high is the ball after 3 seconds?
set t=3 and solve:
h = -16*3^2 + 96*3 + 122
h = -16*9 + 96*3 + 122
h = -144 + 288 + 122
h = 144 + 122
h = 266 feet

How many seconds does it take until the ball finally hits the ground? Round to the nearest tenth of a second.
set h=0 and solve for t:
0 = -16t^2 + 96 t + 122
solve using the quadratic formula to get:
t={-1.1, 7.1}
throw out the negative solution (extraneous) leaving:
t = 7.1 seconds
.
Details of quadratic formula:
*[invoke quadratic "x", -16, 96, 122 ]