Applicare la formula: $\frac{a}{b}c$$=\frac{ca}{b}$, dove $a=1$, $b=5$, $c=\frac{39}{10}$, $a/b=\frac{1}{5}$ e $ca/b=3.9\cdot \left(\frac{1}{5}\right)k^2z$

Applicare la formula: $ab$$=ab$, dove $ab=3.9\cdot 1$, $a=\frac{39}{10}$ e $b=1$

Applicare la formula: $\frac{a}{b}$$=\frac{a}{b}$, dove $a=\frac{39}{10}$, $b=5$ e $a/b=\frac{3.9}{5}$