The harmonic conjugate of (7, 5) with respect to the points (4 , 2) and (9,7) is

P(7,5),A(4,2),B(9,7)  P divided AB¯ in the ratio 4−7:7−9=−3:−2=3:2 Harmonic conjugate of P divides AB¯ in the ratio –3:2 Harmonic conjugate of P is −3B+2A−3+2=(−27,−21)+(8,4)−1=(19,17)