Applicare la formula: $x^2+bx$$=x^2+bx+\left(\frac{b}{2}\right)^2-\left(\frac{b}{2}\right)^2$, dove $b=2$, $bx=2u$, $x=u$, $x^2+bx=u^2+2u$ e $x^2=u^2$

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

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

Applicare la formula: $a^b$$=a^b$, dove $a=1$, $b=2$ e $a^b=1^2$

Applicare la formula: $ab$$=ab$, dove $ab=- 1$, $a=-1$ e $b=1$