Problem: If x + y = 0 is the angle bisector of the angle containing the point (1, 0), for the line 3x + 4y + b = 0, 4x + 3y – b = 0 then b can be

(A) 3

(B) 4

(C) 5

(D) 6

*Ans: ***(C) , (D) **

Sol: (3x + 4y + b) = ± (4x + 3y – b)

For x + y = 0, we have to choose -ve sign.

(3x_{1} + 4y_{1} + b) (4x_{1} + 3y_{1} – b) < 0

⇒ (3 + b) (4 – b) < 0

⇒ b > 4 or b < -3.