If non-zero numbers a, b, c are in H.P., then the straight line xa+yb+1c=0 always passes through a fixed point. That point is
(-1 /2)
(1, - 2)
(-1,-2)
(-1,2)
It is given that a, b, care in H.P
∴ 2b=1a+1c⇒ 1a+(−2)b+1c=0
⇒ xa+yb+1c=0 passes through the fixed point (1, - 2).