Applicare la formula: $ab$$=ab$, dove $ab=9\cdot -8.9$, $a=9$ e $b=-\frac{89}{10}$

Applicare la formula: $\frac{a}{b}+c$$=\frac{a+cb}{b}$, dove $a/b+c=\frac{3}{5}-80.1$, $a=3$, $b=5$, $c=-80.10000000000001$ e $a/b=\frac{3}{5}$

Applicare la formula: $ab$$=ab$, dove $ab=-80.1\cdot 5$, $a=-80.10000000000001$ e $b=5$

Applicare la formula: $a+b$$=a+b$, dove $a=3$, $b=-\frac{801}{2}$ e $a+b=3-400.5$

Applicare la formula: $\frac{a}{b}$$=\frac{a}{b}$, dove $a=-\frac{795}{2}$, $b=5$ e $a/b=-\frac{397.5}{5}$