If $$ {x+{1\over x}}=3$$ then find the value of $$ {x^2}-{1\over {x^2}}$$:

Solve the following equation.

If a\b + b\a =1, then the value of a³+b³ will be 

If $$ {4p\over{{p^2}}-4p+4}={1\over8}$$, p≠0 then the value of $$ {p+{4\over p}}$$

If x - y = 6 and xy = 40, then  find $$ {x^2+y^2}$$

If a =500, b=502 and c=504, then the value of a³ +b³ +c³-3abc

If (a-b)² + (b-c)² + (c-a)² = 0, then find the value of (a³+b³+c³-3abc) ?

If a + a²+a³-1=0, then what is the value of a³ +(1/a)?