Centre of the hyperbola $9{\mathrm{x}}^2-16{\mathrm{y}}^2+72\mathrm{x}-32\mathrm{y}=16$ is

Let S=$9{\mathrm{x}}^2-16{\mathrm{y}}^2+72\mathrm{x}-32\mathrm{y}=16$

 $$\begin{gathered} centre is P.I of \frac{\partial S}{\partial x}=0 and \frac{\partial S}{\partial y}=0 \\ \Rightarrow 18x+72=0 and -32y-32=0 \\ \Rightarrow x=-4 and y=-1 \\ \therefore centre=(-4,-1) \end{gathered}$$