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

If  $$ \ {xy\over x+y}= a, $$ $${xz\over x+z}=b $$ and $$ {yz\over y+z} =c $$  where a, b, c are all non – zero numbers, then x equals to

Simplification 

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

Given that 10^0.48 = x, 10^0.70 = y and x² = y², then the value of z is close to

If p=99, then the value of p(p²+3p+3) will be

Find the value of a and b if (x-1) and (x+1) are factors of x⁴+ax³-3x²+2x+b