Applicare la formula: $x+a=b$$\to x=b-a$, dove $a=x^2$, $b=0$, $x+a=b=x^2+16y=0$, $x=16y$ e $x+a=x^2+16y$

Applicare la formula: $mx=ny$$\to \frac{m}{mcd\left(m,n\right)}x=\frac{n}{mcd\left(m,n\right)}y$, dove $x=y$, $y=x^2$, $mx=ny=16y=-x^2$, $mx=16y$, $ny=-x^2$, $m=16$ e $n=-1$

Applicare la formula: $\frac{a}{b}$$=\frac{a}{b}$, dove $a=16$, $b=16$ e $a/b=\frac{16}{16}$