For the function f(x) = 3x - 225x + 22, find the x-coordinates of the points, if any, at which the graph of each function f has a horizontal tangent line. (Use symbolic notation and fractions where needed. Give your answer in the form of comma separated list if needed. Enter the symbol if there are no such points.) x-coordinates: Find an equation for each horizontal tangent line. (Use symbolic notation and fractions where needed. Let y = f(x) and express equations in terms of y and x. Give your answer in the form of a comma separated list if needed. Enter the symbol if there are no tangent lines.) equations: Solve the inequality f'(x) > 0. (Use symbolic notation and fractions where needed. Give your answers as intervals in the form (*, *). Use the symbol co for infinity, U for combining intervals, and an appropriate type of parenthesis "(", ")", "[" or "]" depending on whether the interval is open or closed. Use the symbol for empty set.) XE Solve the inequality f'(x) < 0. (Use symbolic notation and fractions where needed. Give your answers as intervals in the form (*, *). Use the symbol for infinity, U for combining intervals, and an appropriate type of parenthesis "(", ")", "[" or "]" depending on whether the interval is open or closed. Use the symbol for empty set.) XE