Answer:
D.

Step-by-step explanation:
The wildfire begins at a size of 8 square feet
It means that initial area =8
It then doubles its width every x hours,
and doubles its length every y hours
so, we can set up equation

now, we can simplify it

we are given
After a period of time, the wildfire covers 14,000 square feet
so, we can set A(x,y)=14000
we get


Hi there!
Let's solve this problem step by step!

To find f(3) we must substitute x = 3 into the formula.

Now we use PEMDAS (Parenthesis, exponents, multiply, divide, add, subtract) to find our answer.
Work out the exponents inside the parenthesis first.

And finally multiply.

Hence, the answer is D. 64.
~ Hope this helps you!
During week 2, he could type 15 words per minute, at his fourth week, he could type 30. So 30-15=15. He could type 15 words faster on week 4 than he could at week 2.