Suppose you toss a volleyball to a friend who is 12 ft away. Midway between you and your friend is a volleyball net, the top of which is 7 ft high. The ceiling of the gymnasium is 25 ft high. When you toss the ball to your friend, the shape of its path forms a parabola. The volleyball is 4 ft off the floor when it leaves your hands, and your friend catches the volleyball 4 ft off the floor as well. Write the equation that models the path of the volleyball if it passes midway between the net and the ceiling. Assume the origin is at the base of the volleyball net. Include the vertex, focus, and directrix of the parabola.

Step-by-step explanation:

Halfway between 7ft and 25ft is (7 + 25)/2 = 16ft.

The vertex is (0, 16).

Two other points on the parabola are (-6, 4) and (6, 4).  Since we have the vertex, we only one of these to find the parabola's equation.

y = a(x - h)^2 + k

y = a(x - 0)^2 + 16 for some a.

y = ax^2 + 16 for some a.

Substitute (-6, 4) or (6, 4) for (x, y) and solve for a.

4 = a(6^2) + 16

-12 = 36a

a = -1/3

y = -x^2/3 + 16

You should be able to take it from here.

Step-by-step explanation:

8(-10x+3.5y-7)

8×-10x + 8×3.5y + 8×-7

-80x + 28y - 56

therefore

-80x+28y-56 is the correct answer

what is the original number? you forgot to add it.