Pair Of Straight Lines Question 5
Question: If $ 6x^{2}+11xy-10y^{2}+x+31y+k=0 $ represents a pair of straight lines, then $ k= $
[MP PET 1991]
Options:
A) - 15
B) 6
C) - 10
D) - 4
Show Answer
Answer:
Correct Answer: A
Solution:
$ -6.10k+\frac{11.1.31}{4}-6{{( \frac{31}{2} )}^{2}}+10{{( \frac{1}{2} )}^{2}}-k{{( \frac{11}{2} )}^{2}}=0 $
$ \Rightarrow -k\frac{361}{4}=\frac{5415}{4}\Rightarrow k=-15 $ .
BETA
