The first one is the answe<span>r.</span>
Answer:

Step-by-step explanation:
we know that
A relationship between two variables, x, and y, represent a proportional variation if it can be expressed in the form
or 
so
For 
substitute
------> 
therefore

The equation for this problem can be written as 18x=162. X would represent the number of games bought. You do the inverse operation of multiplying by 18 to both sides and you get the answer as x=9. 9 is the number of games bought with 162 dollars.
Answer:
C. c = (xv - x) / (v - 1).
Step-by-step explanation:
v = (x + c) / (x - c)
(x - c) * v = x + c
vx - vc = x + c
-vc - c = x - vx
vc + c = -x + vx
c(v + 1) = -x + vx
c = (-x + vx) / (v + 1)
c = (-x + xv) / (v + 1)
c = (xv - x) / (v + 1)
So, the answer should be C. c = (xv - x) / (v + 1).
Hope this helps!