It is just a simple revision, but the answer on the guide and my answers are different! So I would appreciate any help, thank you very much :] It would also be great if the method to solving is shown, because whatever I do, the answer is wrong so I wanted to check where I am wrong.(An example of a question too is given in order to get familiar with the question, just in sake. Thankyou)

Eg:- Q. 8^{2/3 }

A. 8^{2/3 }= (2^{3})^{2/3 = }2^{3x2/3 }= 2^{2 }= 4

Math Question : 16^{-1/2}

My answer: 16^{-1/2}= 1/16^{1/2}= 1/ √16 = 1/4

Answer on the guide: 4

I would appreciate any help, Thank you.