Pair Of Straight Lines Question 80
Question: If in general quadratic equation $ f(x,y)=0,\Delta =0 $ and $ a+b=0 $ , then the equation represents
Options:
A) Two parallel straight lines
B) Two perpendicular straight lines
C) Two lines passing through origin
D) None of these
Show Answer
Answer:
Correct Answer: B
Solution:
When the discriminant Δ=0 in the quadratic equation f(x,y)=0, it indicates that the equation represents a pair of coincident lines.
And since a+b=0, the coefficients of $x^2$ and $y^2$ terms have opposite signs, which implies that the lines are perpendicular to each other.
Therefore, the correct answer is B) Two perpendicular straight lines.
BETA
