Answer
2
Work Step by Step
Remember that whenever a fraction is raised to a negative power, we flip the numerator and the denominator of the fraction and make the exponent positive. Thus, we find:
$(16/64)^{-1/2} = (64/16)^{1/2}$
Now, recall the formula:$ a^{b/c}=( \sqrt[c] {a})^{b}$. Thus, we obtain:
$(64/16)^{1/2}=\sqrt{64}/\sqrt{16}=8/4=2$