Question

If the straight line $a x + b y + c = 0$ always passes through

(1, – 2), then a, b, c are.

• A. In A.P.
• B. In H.P.
• C. In G.P.
• D. None of these

Answer 1

Answer: (A)

In A.P.

Answer 2

$a x + b y + c = 0$ is always through $( 1 , - 2 )$.

∴ $a - 2 b + c = 0$ ⇒ $2 b = a + c$

Therefore, a, b and c are in A.P.