Which angle has the same measurement as angle DEA, and how do you know that the measurement is the same?

Combine the information in the problem and the chart using the average balance method to solve the problem.

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

How is this equation completed? i cannot find any examples in the book.