If $$ P={{x^2-36}\over{x^2-49}}$$ and $$ Q={{x+6}\over{x+7}}$$ then the value of $$ {P\over{Q}}$$ is.

If then the value of

If 0.4 m + 0.8 n = 2.2 and 0.8 m + 0.4 n = 1.4, then the value of $$ {m^2}+{n^2}$$ 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: