Let \( A(a,b) \), \( B(3,4) \) and \( C(-6,-8) \) respectively denote the centroid, circumcentre and orthocentre of a triangle. Then, the distance of the point \( P(2a+3,7b+5) \) from the line \( 2x+3y-4=0 \) measured parallel to the line \( x-2y-1=0 \) is:
