Question

If $a,b$ and $c$ are in Arithmetic Progression, the straight line $ax+by+c=0$ will always pass through the point ____

• A. $(-1,-2)$
• B. $(1,-2)$
• C. $(-1,2)$
• D. $(1,2)$

Answer 1

The correct option is B $(1,-2)$

Given a,b,c are in A.P.

$\therefore 2b=a+c$

$\Rightarrow a-2b+c=0$ .....(1)

$\Rightarrow ax+by+c=0$ .....(2)

From eq (1) and eq(2):

$x=1$

$y=-2$

Point $=(1,-2)$

$(Ans\to B)$