4. Find the vertex of 'C'

The \(\triangle ABC\) has the following vertices \(A(\)−9, 12\()\), \(B(\)15, 15\()\) and \(C(x_3\), \(y_3)\). If \(G(\)9, 7\()\) is the centroid, find the values of \(x_3\) and \(y_3\).

 

\(x_3 =\)

 

\(y_3 =\)