If a=x+y, b=x-y, c=x+2y, then $$ {a^2+b^2+c^2}-ab-bc-ca $$ is

If xy(x+y)=1, then $$ {1\over x^3 y^3}-{x^3-y^3}$$ is equal to-

Solve the following equation.

If $${x}^2+{y}^2x+1=0$$ then the value of $$x^{31}+y{35}$$ is

If x²+y²+z² = xy + yz + zx, then the value of $${3x^4+7y^4+5z^4}\over{5x^2y^2+7y^2z^2+3z^2x^2} $$ is

If   $$ {{x+1}\over4x}={5\over 2}$$ then what is the value of   $$ 64x^6+1\over 8x^3  $$

If x = 2 then the value of $$ x^3 + 27x^2 + 243x + 631$$ is:

If a+b = 1 and a³+b³+3ab=k, then the value of k is :