Answer:
seconds
Step-by-step explanation:
When the ball hits the ground, its height will obviously be 0. Therefore, you can set up the equation the following way:

Plugging this into the quadratic equation, you get:

Since the time must be positive, it takes the ball
seconds to hit the ground, or around 3.828. Hope this helps!
Answer:
f(g(-4)) = 13.
g(f(-4)) = -3.
Step-by-step explanation:
g(-4) = (-4)^2 + 3(-4) - 1
= 3.
so f(g(-4))
= f(3)
= 2(3) + 7
= 13.
f(-4) = 2(-4) + 7
= -1.
so g (f(-4))
= g(-1)
= (-1)^2 - 3 - 1
= -3.