plz answer asap

1. Let g(t) = 3t3 12 _ g with g'(t) = 312(12 - 9) - and g" (t) = 18t (12 + 9) (12 - 3) 2 (12 - 3)3 (a) Determine the domain of g. (b) Determine the intervals of increase and decrease. (c) Determine the intervals of concave up and concave down