Answer
Graph $\mathbf{d}$
Work Step by Step
\[\begin{align}
& z=5{{\left( {{x}^{2}}+{{y}^{2}} \right)}^{-1/2}} \\
& z=\frac{5}{\sqrt{{{x}^{2}}+{{y}^{2}}}} \\
& \text{The graph is positive for all ordered pairs }\left( x,y \right). \\
& \text{When }x\rightarrow \pm\infty\text{ and }y\rightarrow \pm\infty, z\rightarrow 0.\\
& \text{When }x\rightarrow 0\text{ and }y\rightarrow 0, z\rightarrow \infty.\\
& \text{The equation matches with the graph }\mathbf{d}\text{.} \\
\end{align}\]
