C: x2+y2−8x=0 H:9x2−4y2=1 By solving 9x2−(48x−x2)=1 $\begin{aligned}
& 4 x^2-72 x+9 x^2=36 \
& \Rightarrow 13 x^2-72 x-36=0 \
& \Rightarrow 13 x^2-78 x+6 x-36=0 \
& \Rightarrow 13 x(x-6)+6(x-6)=0 \
& \Rightarrow x=6 \text { or }-\frac{13}{6} \times \text { neglected } \
& \Rightarrow y^2=8(6)-(6)^2 \
& \Rightarrow y= \pm \sqrt{12}
\end{aligned}So,pointsAandBare(6, \sqrt{12}),(6,-\sqrt{12})P\left(h, \frac{2 h+4}{3}\right)Centroidof\triangle P A Bis\left(\frac{12+h}{3}, \frac{2 h+4}{9}\right)Byoptionsthiscentroidliesonthelive6 x-9 y=20$