[tex]\bf ~~~~~~~~~~~~\textit{negative exponents}
\\\\
a^{-n} \implies \cfrac{1}{a^n}
\qquad \qquad
\cfrac{1}{a^n}\implies a^{-n}
\qquad \qquad
a^n\implies \cfrac{1}{a^{-n}}
\\\\
-------------------------------[/tex]
[tex]\bf \cfrac{6x^2y^4-12x^4y^2}{2x^2}\implies \stackrel{\textit{distributing the denominator}}{\cfrac{6x^2y^4}{2x^2}-\cfrac{12x^4y^2}{2x^2}}
\\\\\\
\cfrac{6}{2}\cdot \cfrac{x^2x^{-2}y^4}{1}-\cfrac{12}{2}\cdot \cfrac{x^4x^{-2}y^2}{1}\implies 3\cdot x^{2-2}y^4~~-~~6\cdot x^{4-2}y^2
\\\\\\
3y^4-6x^2y^2\implies 3y^2(y^2-2x^2)[/tex]
