Find the value of x

A) 3
B) 5
C) 6
D) 8

The graph below shows the height of a projectile t seconds after it is launched. if acceleration due to gravity is -16 ft/s2, which equation models the height of the projectile correctly?

What is the difference between the equations of a vertical and a horizontal line?

Can someone me with #s 8, 9, and 11. with just one of the three also works. prove using only trig identities.