Question 753943
{{{2x^2-4y^2-12y=18}}}


Start this way:
{{{x^2-2y^2-6y=9}}}


Prepare to Complete the Square on the y:
{{{x^2-2(y^2+3y)=9}}}

The term to complete the square is {{{(3/2)^2=9/4}}}


{{{x^2-2(y^2+3y+9/4)=9+9/4}}}
which gives you something factorable on the left side...
...
Can you finish from there?