Question

Suppose that it costs ​$25 to place a classified advertisement in the​ newspaper, plus ​$3 for each line. Then the cost to place an ad x lines long is given by y​ dollars, where y=3x+25. Express an ordered pair the fact that a 2 line ad cost $31

Answer 1

Substitute 2 for x:
y = 3(2) + 25

y = 6 + 25

y = 31

in (x,y) form:
(2, 31)