Answer:

Step-by-step explanation:
The standard form of a quadratic equation is 
The vertex form of a quadratic equation is 
The vertex of a quadratic is (h,k) which is the maximum or minimum of a quadratic equation. To find the vertex of a quadratic, you can either graph the function and find the vertex, or you can find it algebraically.
To find the h-value of the vertex, you use the following equation:

In this case, our quadratic equation is
. Our a-value is 1, our b-value is -6, and our c-value is -16. We will only be using the a and b values. To find the h-value, we will plug in these values into the equation shown below.
⇒ 
Now, that we found our h-value, we need to find our k-value. To find the k-value, you plug in the h-value we found into the given quadratic equation which in this case is 
⇒
⇒
⇒ 
This y-value that we just found is our k-value.
Next, we are going to set up our equation in vertex form. As a reminder, vertex form is: 
a: 1
h: 3
k: -25

Hope this helps!
24/6=4 students
Pencils divided by how many each receive
The formula for finding the circumference is pi times the diameter so If your giving it in terms of pi then you're just finding the diameter which is 15
-16 and -3
I just used 24 and 2, adding &/or subtracting to opposite sides until I got 16*3=48, whether they be positive or negative.
Add -16 and -3 together and you get -19.
Hope this helps you! :)