9 √x Find all critical numbers of the function f(x) = 7√x- If there are multiple critical numbers, separate them with commas. If there are no critical numbers, input DNE. Critical Number(s):

For the given functions f and g, find the requested composite function. f(x)=√√√x +4, g(x) = 8x -8; Find (fog)(x). A. 2√2x+1 OB. 8√x-4 OC. 2√2x-1 OD. 8√x+4-8

Determine the intervals on which the given function is concave up or concave down and find the points of inflection. f(x) — 2хе-9х (Use symbolic notation and fractions where needed. Give your answer as a comma separated list of points in the form in the form (*, *). Enter DNE if there are no points of inflection.) points of inflection: Determine the interval on which f is concave up. (Use symbolic notation and fractions where needed. Give your answer as interval in the form (*, *). Use the symbol o for infinity, U for combining intervals, and an appropriate type of parenthesis "(", ")", "[", "]" depending on whether the interval is open or closed. Enter Ø if the interval is empty.) x E