1)
[tex]\it 3^{93} =3^{3\cdot31} =(3^3)^{31} =27^{31}
\\ \\
4^{62} = 4^{2\cdot31} =(4^2)^{31} =16^{31}
\\ \\
27^{31} \ \textgreater \ 16^{31} \Rightarrow 3^{93}\ \textgreater \ 4^{62} \Rightarrow 3^{93}-4^{62} \ \textgreater \ 0 \Rightarrow
\\ \\
\Rightarrow A= |3^{93}-4^{62}| = 3^{93}-4^{62} [/tex]
2)
[tex]\it ABC-isoscel,\ AB=AC \Rightarrow m(\hat{B}) = m(\hat{C}) \ \ \ \ (1)
\\ \\ \\
DF||BC, \ D\in AB,\ F\in AC \Rightarrow\begin{cases} \m(\widehat{ADF})=m(\hat{B})\ (corespondente) \ \ (2)
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\m(\widehat{AFD})=m(\hat{C})\ (corespondente) \ \ (3)\end{cases} [/tex]
[tex]\it (1),\ (2),\ (3) \Rightarrow ADF-isoscel, AD=AF[/tex]
