If LaTeX: P\left(6,-2\right),\:Q\left(-2,\:8\right),\:R\left(-4,\:3\right),\:P ( 6 , − 2 ) , Q ( − 2 , 8 ) , R ( − 4 , 3 ) ,and LaTeX: S\left(-9,\:y\right)\:S ( − 9 , y )find the value of LaTeX: yy so that LaTeX: PQ\bot RS.