Use finite approximation to estimate the area under the graph of f(x) = 5x² and above the graph of f(x) = 0 from X_0 = 0 to x_n, = 4 using i) a lower sum with two rectangles of equal width
ii) a lower sum with four rectangles of equal width
iii) an upper sum with two rectangles of equal width.
iv) an upper sum with four rectangles of equal width​

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