If a parabola has x-intercepts at 13 and -21, what is the x-coordinate of its vertex

Pleasseee important quick note: enter your answer and show all the steps that you use to solve this problem in the space provided. use the circle graph shown below to answer the question. a pie chart labeled favorite sports to watch is divided into three portions. football represents 42 percent, baseball represents 33 percent, and soccer represents 25 percent. if 210 people said football was their favorite sport to watch, how many people were surveyed?