[tex]\bf a^{-{ n}} \implies \cfrac{1}{a^{ n}}\qquad \qquad
\cfrac{1}{a^{ n}}\implies a^{-{ n}}\\\\
-----------------------------\\\\
thus\implies \cfrac{-9t^{25}}{7t^{26}}\implies \cfrac{-9}{1}\cdot \cfrac{t^{25}}{1}\cdot \cfrac{1}{t^{26}}\cdot \cfrac{1}{7}
\\\\\\ \cfrac{-9}{1}\cdot \cfrac{t^{25}}{1}\cdot t^{-26}\cdot \cfrac{1}{7}\implies
\cfrac{-9}{1}\cdot \cfrac{t^{25}t^{-26}}{1} \cdot \cfrac{1}{7}\implies
\cfrac{-9}{1}\cdot \cfrac{t^{25-26}}{1} \cdot \cfrac{1}{7}
[/tex]
[tex]\bf \cfrac{-9}{1}\cdot \cfrac{t^{-1}}{1} \cdot \cfrac{1}{7}\implies
\cfrac{-9}{1}\cdot \cfrac{1}{t^{1}} \cdot \cfrac{1}{7}\implies \cfrac{-9}{7t}[/tex]
