Which of the following equations is not in function notation?

a. f(x) = x + 3

b. w(r) = 9r - 7

c. y = kx

d. c(w) = w/4

Looks like C, because is the only one without the notation NAME(variable)=...

When the ball hit the ground, the height of the ball will be zero. So using the value of h(x) as zero in the given equation, we can find the time in which the ball will hit the ground.

0 = -(x-2)^2 + 16

(x-2)^2 = 16

x-2 = 16

x-2 = 4

x = 6

This means the ball will hit the ground 6 seconds after Amir threw it.