To evaluate these first we will convert them to exponent form and then evaluate that since we already know how to do that.
(a) These are together to make a point about the importance of the index in this notation. Let's take a look at both of these.
√16 = 16 1/2 = 4 because 42 = 16
Thus, the index is important. Different indexes will provide different evaluations so ensure that you don't drop the index unless it is a 2 (and therefore we're utilizing square roots).