Applicare la formula: $x+a=b$$\to x=b-a$, dove $a=b^3$, $b=40$, $x+a=b=a^3+b^3=40$, $x=a^3$ e $x+a=a^3+b^3$

Applicare la formula: $x^a=b$$\to \left(x^a\right)^{inverse\left(a\right)}=b^{inverse\left(a\right)}$, dove $a=3$, $b=40-b^3$, $x^a=b=a^3=40-b^3$, $x=a$ e $x^a=a^3$

Applicare la formula: $\left(x^a\right)^b$$=x$, dove $a=3$, $b=1$, $x^a^b=\sqrt[3]{a^3}$, $x=a$ e $x^a=a^3$