MCQ
$(x - y){e^{x/(x - y)}} = k$ then
  • A
    $(y - 2x){{dy} \over {dx}} + 3x - 2y = 0$
  • $y{{dy} \over {dx}} + x - 2y = 0$
  • C
    $a{\rm{ }}\left( {y{{dy} \over {dx}} + x - 2y} \right) = 0$
  • D
    None of these

Answer

Correct option: B.
$y{{dy} \over {dx}} + x - 2y = 0$
b
(b) Taking $\log $, we get 

$\log (x - y) + \frac{x}{{x - y}} = \log k$ 

==> $(x - y) - (x - y)\frac{{dy}}{{dx}} + (x - y) - x + \frac{{dy}}{{dx}} = 0$ 

==> $y\frac{{dy}}{{dx}} + x = 2y$.

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