I did this equation on determining quadratic function in vertex form for a parabola on a graph and I found the quadratic function using vertex graphing form. But when I calculated it, it was wrong does anyone know what I did wrong in my calculation?

Will give brainliest for correct answer 8. use the distance time graph to answer these questions: a. what does the graph tell us about the velocity of the car? b. what is the average velocity of the car? (show work) c. is the velocity reflected in the graph positive or negative?d. is there any point on the graph where the car is not moving? how do we know?