Respuesta :

1.
[tex]\dfrac{4x^{3}y^{4}}{-8xy^{2}}=\dfrac{4}{-8}\cdot x^{3-1}y^{4-2}=\dfrac{-x^{2}y^{2}}{2}[/tex]

2.
[tex]\dfrac{3m^{2}-3n^{2}}{6m+6n}=\dfrac{3}{6}\cdot \dfrac{(m+n)(m-n)}{m+n}=\dfrac{m-n}{2}[/tex]