Find all zeros and vertical asymptotes of the rational function
f(x) = (x² - 36)/(x² + 36).
If there is more than one answer, enter your answers as a comma separated list. If there is no solution, enter NONE. Do not leave a blank empty.
(a) The function has x-intercept(s) at x = __________ help (numbers)
(b) The function has y-intercept(s) at y = __________ help (numbers)
(c) The function has vertical asymptote(s) when x = __________ help (numbers)
(d) The function has horizontal asymptote(s) when y = __________ help (numbers)