What is the difference?
x2 - 2x-15
x2 + 2x-35
x2 + 3x + 12
(x-3)(x-5)(x+7)
x(x+3-12)
(x+3)(x-5xx+7)
x² + 3x+12
(x+3)(x-5)(x+7)
x2 + 3x-12
(x+3)(x-5)(x+7)

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