Determine the value(s) of x where the function will have an instantaneous rate of change of 14. (Enter your answers as a comma-separated list. If an answer does not exist, enter DNE.)

f(x) = x3 + 33 x2 + 14 x + 39

1 answer

f'= 3x^2+66x+14=14

3x^2+66x=0
x=0, or x=-22

check that.