Question

if the two lines x+y=5 , kx+2y=0 are parallel then k=

Answer 1

   
$\dfrac{1}{1} = \dfrac{2}{k} \\ \\ \Longrightarrow~~ k = \dfrac{2\times 1}{1} = \boxed{2}$

Answer 2

1/1=2/k
=1*2 =1*k
k=2

hope this help