calculus
posted by anna on .
Determine the value(s) of x where the function will have an instantaneous rate of change of 14. (Enter your answers as a commaseparated list. If an answer does not exist, enter DNE.)
f(x) = x3 + 33 x2 + 14 x + 39

f'= 3x^2+66x+14=14
3x^2+66x=0
x=0, or x=22
check that.