Question

If the straight line $ax+by+c=0$ 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

The correct option is A

In A.P.

Explanation for the correct option.

Given: $ax+by+c=0$ passes through $(1,-2)$.

$$\begin{gathered} \Rightarrow a-2b+c=0 \\ \Rightarrow 2b=a+c \end{gathered}$$

From the basic definition of A.P we can see that $a,b,c$ are in A.P.

Hence option(A) i.e. In A.P. is the correct option.