A caterer has 5 rolls. He is ordering more rolls. He can order up to 9 packages of rolls and each package contains 12 rolls. The caterer cannot order partial packages. The function that models the number of rolls the caterer has is f(p)=12p+5, where p is the number of packages he orders. What is the practical domain of the function?

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:

55 degrees because 55+55=110 degrees