I got X = 6
If you replace x for 6 you should get 216
6^3 = 216
Answer is $114.75. This is found by taking 1.35% of 8,500.
If you list the answer choices, I might be able to help you better.
To answer items such as this, we directly substitute the a + 2 to the all the x's in the function such that,
f(a + 2) = (3 + a + 2) / (a + 2 - 3)
Simplifying the function generated above,
f(a + 2) = (5 + a) / (a - 1)
78 gallons is the same as 312 quarts