Question

If the straight line ax + by + c = 0 always passes through (1, -2), then a, b, c are in
1. A.P.
2. H.P.
3. G.P.
4. None of these

Answer 1

Correct Answer - Option 1 : A.P.

Concept:

If a, b, c are in A.P then 2b = a + c

 

Calculations:

Given, the straight line ax + by + c = 0 always passes through (1, -2).

⇒The point (1, -2) is satisfying the equation of line ax + by + c = 0.

⇒ a(1) +b (-2)+ c = 0

⇒ 2b = a + c

⇒ we can say that 2b = a + c. then a, b, c are in A.P