The answer is A, . This is because when plugging in -2 for x, the expression will look like this: . To make the exponent positive, you have to flip it into a fraction. Then it will be . Lastly, you simplify the denominator into 81.
It could sometimes be proportional. The reasoning here is that if all the items have different prices it won't be, however if the items you are ordering all have the same price they will be!