Applicare la formula: $x+a=b$$\to x+a-a=b-a$, dove $a=1$, $b=0$, $x+a=b=2\sin\left(\frac{1}{5}\right)x+1=0$, $x=2\sin\left(\frac{1}{5}\right)x$ e $x+a=2\sin\left(\frac{1}{5}\right)x+1$

Applicare la formula: $x+a+c=b+f$$\to x=b-a$, dove $a=1$, $b=0$, $c=-1$, $f=-1$ e $x=2\sin\left(\frac{1}{5}\right)x$

Applicare la formula: $ax=b$$\to x=\frac{b}{a}$, dove $a=2$, $b=-1$ e $x=\sin\left(\frac{1}{5}\right)x$

Applicare la formula: $xa=\frac{b}{c}$$\to x=\frac{b}{ac}$, dove $a=\sin\left(\frac{1}{5}\right)$, $b=-1$ e $c=2$