Answer:
The answer would be the last one
Explanation:
Step 1
Factor 64 into its prime factors
64 = 26
To simplify a square root, we extract factors which are squares, i.e., factors that are raised to an even exponent.
Factors which will be extracted are :
64 = 26
No factors remain inside the root !!
To complete this part of the simplification we take the squre root of the factors which are to be extracted. We do this by dividing their exponents by 2 :
8 = 23
At the end of this step the partly simplified SQRT looks like this:
8 sqrt(y16)
Step 2
Rules for simplifing variables which may be raised to a power:
(1) variables with no exponent stay inside the radical
(2) variables raised to power 1 or (-1) stay inside the radical
(3) variables raised to an even exponent: Half the exponent taken out, nothing remains inside the radical. examples:
(3.1) sqrt(x8)=x4
(3.2) sqrt(x-6)=x-3
(4) variables raised to an odd exponent which is >2 or <(-2) , examples:
(4.1) sqrt(x5)=x2•sqrt(x)
(4.2) sqrt(x-7)=x-3•sqrt(x-1)
Applying these rules to our case we find out that
SQRT(y16) = y8
Combine both simplifications
sqrt (64y16) =
8 y8
Simplified Root :
8 y8
hope this helps :)