(1 point) Let f(x) = 7x2 + 4x. At what x-values is f ' (x) zero or undefined? x = (If there is more than one such x- value, enter a comma-separated list; if there are no such x- values, enter "none".) On what interval(s) is f (x) increasing? f (x) is increasing forx in (If there is more than one such interval, separate them with "U". If there is no such interval, enter "none".) On what interval(s) is f (x) decreasing? f (x) is decreasing for x in (If there is more than one such interval, separate them with "U". If there is no such interval, enter "none".) (1 point) Let f (x) = (3x + 8)2. At what x-values is f ' (x) zero or undefined? x = (If there is more than one such x- value, enter a comma-separated list; if there are no such x- values, enter "none".) On what interval(s) is f (x) increasing? f (x) is increasing forx in (If there is more than one such interval, separate them with "U". If there is no such interval, enter "none".) On what interval(s) is f (x) decreasing? f (x) is decreasing for x in (If there is more than one such interval, separate them with "U". If there is no such interval, enter "none".) x2 1 'tLt =. ( pen) 6 f(X) x2_49 At what x-values is f ' (x) zero or undefined? x = (If there is more than one such x- value, enter a comma-separated list; if there are no such x- values, enter "none".) On what interval(s) is f (x) increasing? f (x) is increasing forx in (If there is more than one such interval, separate them with "U". If there is no such interval, enter "none".) On what interval(s) is f (x) decreasing? f (x) is decreasing for x in (If there is more than one such interval, separate them with "U". If there is no such interval, enter "none".) (1 point) Let f (x) = 6 9x. At what x-values is f ' (x) zero or undefined? x = (If there is more than one such x- value, enter a comma-separated list; if there are no such x- values, enter "none".) On what interval(s) is f (x) increasing? f (x) is increasing for x in (If there is more than one such interval, separate them with "U". If there is no such interval, enter "none".) On what interval(s) is f (x) decreasing? f (x) is decreasing for x in (If there is more than one such interval, separate them with "U". If there is no such interval, enter "none".)