Pair Of Straight Lines Question 94
Question: The equation $ 12x^{2}+7xy+ay^{2}+13x-y+3=0 $ represents a pair of perpendicular lines. Then the value of a is
[Karnataka CET 2001]
Options:
A) $ \frac{7}{2} $
B) - 19
C) - 12
D) 12
Show Answer
Answer:
Correct Answer: C
Solution:
Comparing the given equation with standard equation, we get $ a=12 $ and $ b=a $ . We also know that for perpendicular lines, coefficient of $ x^{2} $ + coefficient of $ y^{2}=0 $ or $ a+b=0 $ . Therefore $ 12+a=0 $ or $ a=-12 $ .
BETA
