Applicare la formula: $\frac{a}{b}+c$$=\frac{a+cb}{b}$, dove $a/b+c=\frac{7}{9}-1$, $a=7$, $b=9$, $c=-1$ e $a/b=\frac{7}{9}$

Applicare la formula: $a+b$$=a+b$, dove $a=7$, $b=-9$ e $a+b=7-9$

Applicare la formula: $x^a$$=\frac{1}{x^{\left|a\right|}}$

Applicare la formula: $\frac{a}{b}\frac{c}{f}$$=\frac{ac}{bf}$, dove $a=7$, $b=9$, $c=1$, $a/b=\frac{7}{9}$, $f=x^{\left|-\frac{2}{9}\right|}$, $c/f=\frac{1}{x^{\left|-\frac{2}{9}\right|}}$ e $a/bc/f=\frac{7}{9}\frac{1}{x^{\left|-\frac{2}{9}\right|}}$

Applicare la formula: $\frac{a}{b}\frac{c}{f}$$=\frac{ac}{bf}$, dove $a=7$, $b=9$, $c=1$, $a/b=\frac{7}{9}$, $f=\sqrt[9]{x^{2}}$, $c/f=\frac{1}{\sqrt[9]{x^{2}}}$ e $a/bc/f=\frac{7}{9}\frac{1}{\sqrt[9]{x^{2}}}$