Q122 / 225 · JEE Main 2004 · Mathematics

If the sum of the slopes of the lines given by $x^2-2 c x y-7 y^2=0$ is four times their product, then $c$ has the value

  • A
    1
  • B
    $-1$
  • Correct answer
    C
    2
  • D
    $-2$

Solution

$m_1+m_2=-\frac{2 c}{7}$ and $m_1 m_2=-\frac{1}{7}$ $m_1+m_2=4 m_1 m_2 \quad$ (given) $\Rightarrow c=2$

Hence, the correct answer is option: 'C'.

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