A maintenance company charges a monthly fee to clean office buildings. The fee is based on the number of employees in the office. An office with 15 employees pays $150 per month while an office with 27 employees pays $246 per month. Which of the following functions represents the relationship between the monthly cost and x, the number of employees? A. f(x) = 8x
B. f(x) = 8x + 30
C. f(x) = 12x + 94
D. f(x) = 6x + 84

The Answer here is B.

Step-by-step explanation

So, 15 * 8 = 120, but it's $150 a month, so 30 is remaining after 120. 150 is f(8) if B was the answer.

27 * 8 is 216, and then we add 30 again for 246. So 246 is f(27).

To determine whether a solution a set of a system of linear inequalities is right, you simply plug back into the equation to check your work. If the solution equals and is mathematically correct, then that's the answer. For Example, use the equation,

5x = 10

Let's say you got an answer of x = 4. Plug it back into the equation 
5(4) ≠ 10. As you can see the answer is wrong. This shows you that the answer is wrong. 

The correct answer is x = 2