If p³ – q³ = (p-q)[(p-q)²+xpq)] then the value of x is

If $$ {x+{1\over x}=7}$$ then $$ {x^{2}+{1\over {x^{2}}}=?}$$

if a=26 and b=22, then the value of   $${{a^3-b^3}\over {a^2-b^2}}-{3ab\over a+b}$$ is

If a = 7, b = 5 and c = 3, then the value of $$a^2+b^2+c^2-ab-bc-ca$$ is 

$$ {x^{8}+4\over{x^{4}+2x^{2}+2}}$$ is equal to

 If 3x²-5x+1=0, then the value of ( $$x^2+{1\over 9x^2}$$) is 

If a=25, b=15 , c=-10 then find the value of $$ {a^{3}+b^{3}+c^{3}-3abc\over {(a-b)^{2}+(b-c)^{2} +(c-a)^{2}}}$$

If x = a - b, y = b - c, z = c - a, then the numerical value of the algebraic expression x³ +y³ + z³ -3xyz will be