Solve[{x==((1+(v/c))/(1-(v/c))),y==((2(1+(v/c)))/((u/c)(1-(v/c))))},{u,v}][[1]]
Collect[Simplify[(((((1+x))^2) (y^2))/(4x (c^2)(1-(c^4) d) ))((u^2)+(v^2)-(c^2)(1+d (u^2)(v^2))/.%)],x]
Collect[Simplify[(((1-(c^4) d))^3)(%/.{x->(x/(1-(c^4) d))+((2 ((c^4) d+1))/(3 ((c^4) d-1))),y-> (y/(1-(c^4) d))})],{x,y}]