64
Step-by-step explanation:
[tex]\begin{aligned}\rm f(x)&=\rm\frac{1}{2}\times 2^x\\\rm f(7)&=2^{-1}\times 2^7\\&=2^{-1+7}\\&=2^{7-1}\\&=2^6\\&=2^6\\&=\bf 64\end{aligned}[/tex]
