Answers by visitors named: Vegasjuju

The tests are slight different. Pay attention. 5.D - The speed of the car decreases from 4 mi/h to 2 mi/h in the first 3 seconds, increases to 5 mi/h in the next 5 seconds, and then remains at 5 mi/h for the last 2 seconds.

The vertex of f(x) is a minimum when a>0. The vertex of f(x) is a maximum when a<0. This is the right answer, Just did the test.