posted by Eric .
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 = 33x2 − 2145x + 43,000 (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?
x = ___ mi per gallon
I'm not sure what formula to use to solve this equation. As well as how to get the answer. How should I approach this problem?