If f(x)+5x -2 and g(x)+2x+1 find (f+g)(x)

Find the absolute maximum and absolute minimum values of the function f(x)= x^3+12x^2−27x+12 over each of the indicated intervals. (a) interval = [−10,0] absolute max and min (b) interval = [−7,2] absolute max and min (c) interval = [−10,2] absolute max and min