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Question: Answered & Verified by Expert
If slope of one line of \(a x^2+4 x y+y^2=0\) is 3 times the other, then the value of ' \(a\) ' is
MathematicsPair of LinesAP EAMCETAP EAMCET 2020 (21 Sep Shift 2)
Options:
  • A -3
  • B -1
  • C 3
  • D 1
Solution:
2232 Upvotes Verified Answer
The correct answer is: 3
Let the slope of lines are \(m\) and \(3 m\) respectively which are represented by \(a x^2+4 x y+y^2=0\)
\(\because\) Sum of slopes \(=m+3 m=-\frac{4}{1}=-4 \Rightarrow m=-1\) and product of the slopes \(=m(3 m)=\frac{a}{1} \Rightarrow m^2=\frac{a}{3}\)
\(\therefore \quad(-1)^2=\frac{a}{3} \Rightarrow a=3\)
Hence, option (c) is correct.

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