Awater tank is being filled with water. before water is pumped in, the water level in the tank is 11 inches high. after 20 minutes, the water level is 58 inches high. make an equation for this? will give brainest answer

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