If an object is dropped from a height of 85 feet, the function h(t) = -16t^2 + 85 gives the height of the object after t seconds. Approximately, when will the object hit the ground? 85.00 seconds, 69.00 seconds, 0.33 seconds, 2.30 seconds

Astudent draws two parabolas on graph paper. both parabolas cross the x-axis at (–4, 0) and (6, 0). the y-intercept of the first parabola 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? write your answer as a decimal rounded to the nearest tenth