2x^2-4xy-y^2
=2(x^2-2xy+y^2)-3y^2
=2(x-y)^2-(√3y)^2
=[√2(x-y)]^2-(√3y)^2
=[√2(x-y)+(√3y)][√2(x-y)-√3y]
=[√2x+(√3-√2)y)][√2x-(√3+√2)y]
2x^2-4xy-y^2
=2(x^2-2xy+y^2)-3y^2
=2(x-y)^2-(√3y)^2
=[√2(x-y)]^2-(√3y)^2
=[√2(x-y)+(√3y)][√2(x-y)-√3y]
=[√2x+(√3-√2)y)][√2x-(√3+√2)y]