The answer is:  " 2x¹⁶ y " .
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This is the "most simplified" version of the expression given.
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Explanation:
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Given:  "2xy (x⁵)³ " ;  Simplify .
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Note:  (x ⁵) ³ = x⁽ ⁵ * ³ ⁾  =  x ⁽¹⁵⁾ ;
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Rewrite:  
2xy (x⁵)³ = 2xy x⁽¹⁵⁾ ; 
Rewrite:
2 * x * x⁽¹⁵⁾ * y ;
Note:   "x * x⁽¹⁵⁾ = x¹  *  x¹⁵  = x⁽¹ ⁺ ¹⁵⁾ = x¹⁶ ;
Rewrite:  " 2x¹⁶ y " .
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