Question

domain f(x)= 1/(sqrt(8x-16)

Answer 1

$\sf f(x)=\dfrac{1}{\sqrt{8x-16}}$

Now

$\\ \sf\longmapsto \sqrt{8x-16}\neq 0$

$\\ \sf\longmapsto 8x-16\neq 0$

$\\ \sf\longmapsto 8x=16$

$\\ \sf\longmapsto x=\dfrac{16}{8}$

$\\ \sf\longmapsto x=2$

Hence

$\\ \sf\longmapsto D_f=R-\{2\}$