Applicare la formula: $ab$$=ab$, dove $ab=0.2\cdot 57\left(-\frac{1}{2}\right)$, $a=\frac{1}{5}$ e $b=57$

Applicare la formula: $\frac{a}{b}c$$=\frac{ca}{b}$, dove $a=-1$, $b=2$, $c=\frac{57}{5}$, $a/b=-\frac{1}{2}$ e $ca/b=11.4\left(-\frac{1}{2}\right)$

Applicare la formula: $ab$$=ab$, dove $ab=11.4\cdot -1$, $a=\frac{57}{5}$ e $b=-1$

Applicare la formula: $\frac{a}{b}$$=\frac{a}{b}$, dove $a=-\frac{57}{5}$, $b=2$ e $a/b=-\frac{11.4}{2}$