Tabatha we shooting free throws in gym class she completed nine of the shots which was the third of four more than joan completed what is the number of free throws the joan completed

Astudent draws two parabolas both parabolas cross the x axis at (-4,0) and (6,0) the y intercept of the first parabolas is (0,-12). the y intercept of the second parabola is (0,-24) what is the positive difference between the a values for the two functions that describe the parabolas