Applicare la formula: $ax=b$$\to \frac{ax}{a}=\frac{b}{a}$, dove $a=i$, $b=-\frac{8}{9}$ e $x=smx$

Applicare la formula: $\frac{a}{a}$$=1$, dove $a=i$ e $a/a=\frac{ismx}{i}$

Applicare la formula: $xa=\frac{b}{c}$$\to x=\frac{b}{ac}$, dove $a=mx$, $b=-\frac{8}{9}$, $c=i$ e $x=s$

Applicare la formula: $\frac{\frac{a}{b}}{c}$$=\frac{a}{bc}$, dove $a=-8$, $b=9$, $c=mxi$, $a/b/c=\frac{-\frac{8}{9}}{mxi}$ e $a/b=-\frac{8}{9}$