The correct answer is A.
You have direct variation if x and y are modeled by the equation

In this case, m is the constant of proportionality. So, if the constant has to be 2, the equation becomes

A side note: Actually, option C has a constant of proportionality of two as well, except the roles of x and y are interchanged. I chose option A because usually you want the y = mx form, but the names of the variables are obviously meaningless.
First subtract the installation price:
6855-85= 6,770
Then divide 6,770 by 24(12 months in 1 yr.):
6770/24= $282.08
Your monthly fee is $282.08
By rearranging x = 7y - 5 to make y the subject, we get
x + 5 = 7y ( By transposition method )
or, 
<h2>Answer:</h2>

Step-by-step explanation:
304
plug 4 in for x
3(4)^2 + 4(4)^3 = 304
48 + 256 = 304