Suppose that it costs $25 to place a classified advertisement in the newspaper, plus $4 for each line. then the cost to place an ad x lines long is given by y dollars, where y= 4x + 25.
express as an ordered pair the fact that a 14 line cost $81. _
express as an ordered pair the fact that an ad costing $37 is 3 lines long. _

Hello.

We have a function y = f(x), that associates for each value of x a value in y. We represent this in a ordered pair (x, y). In this exercise, we have the price in function of the number of lines, so, the first element of the pair is the number of lines and the following is the price.

Therefore, for 14 lines and $81, we have x = 14 and y = 81 and the pair is:

(14, 81)

b) The cost is the value in y, so, we have y = 37 and x = 3. The pair is:

(3, 37)