Quantity of farmland owned by Pam = 7.5 square miles.
The other important information given in the question is the equation relating square miles and acres. Using that information, the answer to the question can be easily reached.
a = 640s
= 640 * 7.5 acres
= 4800 acres.
From the above deduction, we can conclude that the correct option among all the options that are given in the question is the third option or option "C".
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!
The answer is 0.382 a liter
[ 2x + y = -9 ] x -3
[- 3x +11= y ] x 2
-6x -3y = 27
-6x + 22 = 2y
-6x +27 = 3y
-6x +22 = 2y
5 = y
-6x -3x5 = 27
-6x -15 = 27
-6x = 42
-x = 42/6
-x = 7
x = -7
answer
x = -7
y = 5