Applicare la formula: $\frac{a^m}{a^n}$$=a^{\left(m-n\right)}$, dove $a^n=f^{-18}$, $a^m=f^{-15}$, $a=f$, $a^m/a^n=\frac{f^{-15}y^{-32}t^{21}}{f^{-18}y^{-34}t^{25}}$, $m=-15$ e $n=-18$

Applicare la formula: $\frac{a^m}{a^n}$$=a^{\left(m-n\right)}$, dove $a^n=y^{-34}$, $a^m=y^{-32}$, $a=y$, $a^m/a^n=\frac{f^{3}y^{-32}t^{21}}{y^{-34}t^{25}}$, $m=-32$ e $n=-34$

Applicare la formula: $\frac{a^m}{a^n}$$=\frac{1}{a^{\left(n-m\right)}}$, dove $a=t$, $m=21$ e $n=25$

Applicare la formula: $a+b$$=a+b$, dove $a=25$, $b=-21$ e $a+b=25-21$