<s>[INST] Simplify this expansion : $\omega=(28+(\frac{5290}{3})^{\frac{3}{2}})^{\frac{1}{3}}+(28-(\frac{5290}{3})^{\frac{3}{2}})^{\frac{1}{3}}$ Find a simple closed form of : 
$\omega=(28+(\frac{5290}{3})^{\frac{3}{2}})^{\frac{1}{3}}+(28-(\frac{5290}{3})^{\frac{3}{2}})^{\frac{1}{3}}$
My try : 
Let : 
$A=(28+(\frac{5290}{3})^{\frac{3}{2}})^{\frac{1}{3}}$ 
And 
$B=(28-(\frac{5290}{3})^{\frac{3}{2}})^{\frac{1}{3}}$ 
Now : 
$A^{3}+B^{3}=56$ 
But how I can now find $A$ and $B$ ? 
 [/INST] I would write
$$(28+x)^{1/3}+(28-x)^{1/3}=s$$ and now raise this to the power three.
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