Plot of the graph

Hello,

I don't know, how to define a plot of the trajectory:

a * ln (abs(x2)) - b * x2 + c * ln (abs(x1)) - d * x1 = Cn
where a,b,c and d are constants (a=b=c=d=1)?
And how define variables x1 and x2?

Please, it's very important for me. Thanks

Zajda

[Azzi Abdelmalek]

What are x1 and x2? What do they represent?