If 5^√x + 12^√x = 13^√x, then x is equal to: 

If average of two x and $$1\over x$$ (where x ≠ 0) is A, what will be the average of x³ and $$1\over {x^3}$$?

simplify the following equation
$$ (1-{1\over3})(1-{1\over4})(1-{1\over5})......(1-{1\over n})$$

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: