Georgia needs to buy some cheese. An 8-ounce package of cheddar cheese costs $3.50. A 12-ounce package of cheddar
cheese costs $5.25. Which is the better buy? How many cents
per ounce cheaper is the better buy?

neither buy is better, both buys are $2.28571428/ounce

the direct variation says that:

then the equation is of the form is given by:

            where k is the constant variation.

from the given table:

consider any value of x and m(x)=y

x = 2 and m(x)=y = 3

substitute these value in [1]; we have;

divide both sides by 2 we get;

⇒

check:

put x = -1 and m(x) = -1.5

substitute in the equation:

-1.5 = -1.5                   true

therefore, the function m(x) represents a direct variation

graph of this function as shown below: