Answer:
Step-by-step explanation:In this problem, cost is a function of time (since 2003). It is a linear function. That means the graph is a straight line.remember the equation for a line is: y = mx + b where m is the slope and b is the y-interceptx-axis is time since 2003, or x = time (in years since 2003)y-axis is cost of gas per gallon, or y = coststarts in 2003, so this represents x = 0, and the cost was $1.75 at x = 0 - this makes the y-intercept 1.75m is the slope, which is the change in y divided by the change in x:(3.50 - 1.75)/(2013 - 2003) = 1.75/10 = 0.175b is the y-intercept which is 1.75 which we got from the starting cost in 2003 which we consider x = 0 (or time = 0)so the model is: y = 0.175x + 1.75to find the cost of gas in another year, calculate x = (new year - 2003) then plug it into your model. I'm guessing Part B,) should read 2023 (not 2003) then the model would be:y = 0.175(20) + 1.75 = $5.25 per gallon of gas