Applicare la formula: $a+\frac{b}{c}$$=\frac{b+ac}{c}$, dove $a=-1$, $b=2$, $c=x$, $a+b/c=\frac{2}{x}-1$ e $b/c=\frac{2}{x}$

Applicare la formula: $\frac{\frac{a}{b}}{\frac{c}{f}}$$=\frac{af}{bc}$, dove $a=2$, $b=x$, $a/b/c/f=\frac{\frac{2}{x}}{\frac{2-x}{x}}$, $c=2-x$, $a/b=\frac{2}{x}$, $f=x$ e $c/f=\frac{2-x}{x}$

Applicare la formula: $\frac{a}{a}$$=1$, dove $a=x$ e $a/a=\frac{2x}{x\left(2-x\right)}$