Can someone explain me how to do this

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

Ineed to know how to write question one in mathematical terms

Mr. jones determined that the equation y = 98 - 16/5 x could be used to predict his students' unit test scores, based on the number of days, x, a student was absent during the unit. what was the meaning of the y-intercept of the function? (by the way the 16/5 is a )