1.
If in triangle ABCABC, A(1,10)A \equiv (1,10), circumcentre (13,23)\equiv \left(-\frac{1}{3}, \frac{2}{3}\right) and orthocentre (113,43)\equiv \left(\frac{11}{3}, \frac{4}{3}\right) then the co-ordinates of mid-point of side opposite to AA is-