Consider the function f(x)=2x - 6x 90x+6 on the interval -4,9] Find the average or mean slope of the function on this interval By the

Consider the function f(x)=2x² - 6x² 90x+6 on the interval -4,9] Find the average or mean slope of the function on this interval By the Mean Value Theorem, we know there exists at least one e in the open interval (-4,9) such that f'(e) is equal to this mean slope Find all values of e that work and list them (separated by commas) in the box below. If there are no values of c that work, enter None List of numbers