I need help solving these two problems:

Problem #1:

For the function graphed below, complete the following. (Enter your answers using interval notation.) 2 X -4 4 - 2 4 (a) Find the intervals on which the derivative is positive. (b) Find the intervals on which the derivative is negative.Make a sign diagram for the derivative of the function. f(x) = x3 - 3x2 - 9x + 8 F ( x ) ? 30 f ( x ) ? 30 f ( x ) ? 30 f ( x) ? 30 f ( x ) ? 30 X = X = Find all open intervals of increase and decrease. (Enter your answers using interval notation.) increase decrease Sketch the graph of the function. 15 106 -4 -2 2 -4 -2 X 4 WebAssign Plot - 156 O - 15 O 15 -4 X - 4 -2 2 X -5 -10 - 15 O