If $$ {x+{1\over {x}}=1}$$, then find the value of $$ {x^{208}+{x^{205}+x^{204}+x^{201}}}$$.

if a³b = abc = 180, a, b, c are positive integers, then the value of c is 

If bc+ab+ca=abc, then the value of $$ {b+c\over {bc(a-1)}}+{a-c\over {ac(b-1)}}+{a+b\over {ab(c-1)}}$$ is

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

Solve the following equation.

If a-b=10 and ab=-21, then what is the value of a³-b³?

 $${a\over b}={2\over3}$$ and $${b\over c}={4\over5}$$ then the ratio  $${a+b}\over {b+c}$$ equal to:

If a²=b+c, b²=c+a  and c²=a+b then the  value of $$ {1\over{1+a}}+{1\over{1+b}}+{1\over{1+c}}$$ is