Respuesta:
La 125.
[tex]64 - {x}^{3} = {4}^{ 3} - {x}^{3} \\ = (4 - x)( {4}^{2} + 4x + {x}^{2} ) \\ = (4 - x)(16 + 4x + {x}^{2} )[/tex]
