Applicare la formula: $ab$$=ab$, dove $ab=2\cdot -3.9$, $a=2$ e $b=-\frac{39}{10}$

Applicare la formula: $a+b$$=a+b$, dove $a=-\frac{39}{5}$, $b=-8$ e $a+b={\left(-3.9\right)}^2-7.8-8$

Applicare la formula: $a^b$$=a^b$, dove $a=-\frac{39}{10}$, $b=2$ e $a^b={\left(-3.9\right)}^2$

Applicare la formula: $a+b$$=a+b$, dove $a=15.209999999999999$, $b=-\frac{79}{5}$ e $a+b=15.21-15.8$

Applicare la formula: $\frac{a}{b}$$=\frac{a}{b}$, dove $a=4$, $b=-\frac{59}{100}$ e $a/b=\frac{4}{-0.59}$