hmmmm I only see one operation, the green one atop, so I'll nevermind the others, unless you say otherwise somehow.
[tex]\bf -\cfrac{a}{b}= \begin{cases} \cfrac{-a}{b}\\[2em] \cfrac{a}{-b} \end{cases}\qquad \qquad \textit{so for example}\qquad -\cfrac{2x+3y-z}{3} \\\\\\ \cfrac{-(2x+3y-z)}{3}\implies \cfrac{-2x-3y+z}{3} \qquad or \qquad \cfrac{2x+3y-z}{-3}[/tex]
so the negative number upfront, in that example namely -1, can be absorbed by either the numerator or denominator, but in front it means it applies to the whole fraction, and then you can have either one absorbe it, and you can write the fraction without it upfront, since it'd had been expanded already in the fraction.
[tex]\bf -\cfrac{2}{3}\times\cfrac{5}{-6}\implies \cfrac{-10}{-18}\implies \cfrac{-5}{-9}\implies \cfrac{5}{9}[/tex]
