Applicare la formula: $x+a=b$$\to x=b-a$, dove $a=7\sqrt[4]{x^{3}}$, $b=7$, $x+a=b=7\sqrt[4]{x^{3}}+\sqrt[4]{y^{3}}=7$, $x=\sqrt[4]{y^{3}}$ e $x+a=7\sqrt[4]{x^{3}}+\sqrt[4]{y^{3}}$

Applicare la formula: $x^a=b$$\to \left(x^a\right)^{inverse\left(a\right)}=b^{inverse\left(a\right)}$, dove $a=\frac{3}{4}$, $b=7-7\sqrt[4]{x^{3}}$, $x^a=b=\sqrt[4]{y^{3}}=7-7\sqrt[4]{x^{3}}$, $x=y$ e $x^a=\sqrt[4]{y^{3}}$

Applicare la formula: $\left(x^a\right)^b$$=x$, dove $a=\frac{3}{4}$, $b=4$, $x^a^b=\sqrt[3]{\left(\sqrt[4]{y^{3}}\right)^{4}}$, $x=y$ e $x^a=\sqrt[4]{y^{3}}$