Applicare la formula: $\frac{a}{b}c$$=\frac{ca}{b}$, dove $a=1$, $b=4$, $c=-5$, $a/b=\frac{1}{4}$ e $ca/b=-5\left(\frac{1}{4}\right)$

Applicare la formula: $ab$$=ab$, dove $ab=-5\cdot 1$, $a=-5$ e $b=1$

Applicare la formula: $\frac{a}{b}\frac{c}{f}$$=\frac{ac}{bf}$, dove $a=\frac{1}{4}\cdot +1$, $b=5$, $c=-\frac{5}{4}$, $a/b=\frac{\frac{1}{4}\cdot +1}{5}$, $f=3$, $c/f=\frac{-\frac{5}{4}}{3}$ e $a/bc/f=\frac{\frac{1}{4}\cdot +1}{5}\cdot \frac{-\frac{5}{4}}{3}$