find an $x^{\prime} y^{\prime}$-equation for the graph of the given $x y$-equation so that the center or, in the case of a parabola, the vertex, of the graph is at the origin in the $x^{\prime} y^{\prime}$-system. Sketch the curve, showing both sets of coordinate axes, and identify the type of curve.
$4 x^2-9 y^2-16 x+18 y-7=0$