A car’s total stopping distance in feet depends on many factors, but can be approximated by the expression [math]\frac{11}{10}x + \frac{1}{19}x^2[/math], for which [math]x[/math] is the speed of the car in miles per hour. Is this expression quadratic? What effect does doubling the car’s speed from [math]10[/math] mph to [math]20[/math] mph have on the total stopping distance?
