Answer
Fill the blanks with
$ y $
$ x=0$
vertical
Work Step by Step
$ f(x)=b^{x}$ and $ g(x)=\log_{b}x $ are inverse functions.
Their graphs are reflections about the line $ y=x.$
$ b^{x}$ has a horizontal asymptote, the x-axis $(y=0)$.
so $\log_{b}x $ has a vertical asymptote, the y-axis $(x=0)$
Fill the blanks with:
$ y $
$ x=0$
vertical