$$ {a^2-b^2-2bc-c^2}\over{a^2+b^2+2ab-c^2}$$ is equal to

If $$ {8x\over{2x^{2}+7x-2}}=1, x>0,$$ then what is the value of of $$ {x^{3}+{1\over x^{3}}}$$ ?

If x + y = 1 and xy (xy – 2) = 12,then the value of x⁴ + y⁴ is:

If $$ {x=a^{2\over3}-a^{-2\over3}}$$ then the value of $$ {x^{3}+3x}$$.

If $$x=(\sqrt2+1)^{1\over3} $$, the value of $$(x^3-{1\over {x^3}}) $$ is

If $$ {\sqrt{2x+9}+x=13}$$ then find the value of x?

If  $$\sqrt{a}+\sqrt{b}=15 \ and \ (\sqrt{a}-\sqrt{b} )=3$$ then the value of $$\sqrt{ab/4} $$ is 

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