Answer
Please see below.
Work Step by Step
The graph of $g(x)=-2\log_2x$ (the red graph) is the graph of $f(x)=\log_2x$ (the blue graph) vertically stretched by $2$ and then reflected about the $x$-axis.
Looking at the graph, we observe that the vertical asymptote is $x=0$.
We also find that the domain and the range of the function $g(x)$ are$$D_g=(0, \infty ) \quad \text{ and } \quad R_g= (- \infty, \infty ),$$respectively.
