The amount of carbon dioxide (in pounds per 15,000 cubic miles) released by a certain suv depends on its fuel efficiency according to the formula w = 32x2 − 2080x + 44,000 (12 ≤ x ≤ 33) where x is the fuel efficiency of an suv in miles per gallon. according to the model, what is the fuel efficiency of the suv with the least carbon dioxide pollution?

30 miles per gallon.

Explanation:

See picture  

When the amount of carbon is plotted based on efficiency, the following graph is obtained (see image)

when looking at the graph, it can be seen that the point of lowest emission is presented with the maximum possible efficiency, 30 miles per gallon and this value is 10400 pounds per 15000 cubic miles.  

the correct answer would be b) volume versus temperature, because they are also directly proportional.