Answer
$1$
Work Step by Step
We have
$$
\operatorname{Jac}(G)=\frac{\partial(x, y)}{\partial(u, v)}=\left|\begin{array}{ll}
{\frac{\partial x}{\partial u}} & {\frac{\partial x}{\partial v}} \\
{\frac{\partial y}{\partial u}} & {\frac{\partial y}{\partial v}}
\end{array}\right| =\left|\begin{array}{ll}
{ 2} & {1} \\
{5} & {3}
\end{array}\right| =6-5=1.
$$
