Solve the following inequality. Write the answer in interval notation. Note If the answer includes more than one interval write the intervals separated by the "union" symbol, U. If needed, enter (infinity sign) as infinity and -(infinity sign) as -infinity.

x^3 - 16x </=0

Answer: ?

I realize this might be easy for you guys but it isn't obvious to me and an explanation would be greatly appreciated!

Thanks in advance!