Question

If non-zero numbers a, b, c are in HP, then the straight line (x/a) + (y/b) + (1/c) = 0 always passes through a fixed point that point is

(a) [1, – (1/2)] 

(b) (1, – 2)

(c) (– 1, – 2)

(d) (– 1, 2)

Answer 1

The correct option (b) (1, – 2)   

Explanation:

a, b, c are in H.P.

hence (2/b) = (1/a) + (1/c)

i.e. (1/a) – (2/b) + (1/c) = 0

equation of line is (x/a) + (y/b) + (1/c) = 0

∴ x = 1 & y = – 2 ⇒ it passes through (1, – 2)