A rock is thrown from the top of a tall building. The distance, in feet, between the rock and the groundt seconds after it is thrown is given by d = - 16t^2-2t+ 733. How long after the rock is thrown is it 400 feet
from the ground?
37/8 s
b. 45/8 s
c. 11/2 s
d. 9/2 s
a. 37/8

a and c

for infinitely many solutions we require both left and right sides to be equal

distribute and simplify

a

14 - 8x = 20 - 8x - 6 = 14 - 8x ← both sides equal so infinite solutions

b

6x - 54 = 6x - 54 + x = 7x - 54 ← not equal

c

4x + 16 = 4x + 10 + 6 = 4x + 16 ← both sides equal so infinite solutions

d

5x - 40 + 10 = 5x + 10

5x - 30 = 5x + 10 ← not equal

arc length = radius * x ( in radians)

6 * pi = 18 * x

divide by 18 on each side

6 pi / 18 = x

pi/3 = x

the angle is pi / 3 radians

or   60 degrees