If `x=2,y=1` then `x^(4)+2x^(3)y-2xy^(3)-y^(4)` is equal to

If x^(2)+y^(2)=1 and P=(3x-4x^(3))^(2)+(3y-4y^(3))^(2) then P is equal to

If x^2+y^2=1 and P=(3x-4x^3)^2+(3y-4y^3)^2 then P is equal to

If x:y=4:5 , then (2x+3y): (8x-5y) is equal to :

If 1/x-1/y=4 then (2x+4xy-2y)/(x-y-2xy)=

If x+y=3 and xy=2, then find x^(4)+y^(4)

What is ((x^(2)+y^(2))(x-y)-(x-y)^(3))/(x^(2)y-xy^(2)) equal to ?

x = (sqrt3 + 1)/(sqrt3 - 1) and y = (sqrt3 - 1)/(sqrt3 + 1) . Then (x^2 + xy + y^2)/(x^2 -xy + y^2) is equal to :

x"@"y=(x+y)^(2) x#y=(x-y)^(2) (2" @ "2)+(3#3)-(4"@"4)+(5#5) is equal to :