What are the coordinates of the circumcenter of the triangle with vertices A(2,7), B(10,7) and C(10,3) WILL GIVE ALL POINTS PLS

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