The vertices of a triangle are functional values of corresponding matrix
1 -1 2
3 1 0
of (1,2,1), (2,1,1), (1,3,1).
A variable straight line passing through the point which is a functional value of (1,2,1) of the corresponding matrix intersects ax2+2hxy+by2=0 at A& B. Find the locus of midpoint of AB.