Given the function f(x) = -x² + 8x + 9, state whether the vertex represents a maximum or minimum point for the function. What about the quadratic function the way it is written indicates if it is a maximum or a minimum? Explain your answer.

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