[tex]a)\\32^{13}=2^{5\cdot 13}=2^{65}\\
8^{21}=2^{3\cdot21}=2^{63}\\
32^{13}\ \textgreater \ 8^{21}\\
b)\\8^{17}=2^{3\cdot17}=2^{51}\\
16^{12}=2^{4\cdot 12}=2^{48}\\
8^{17}\ \textgreater \ 16^{12}\\
c)\\27^{13}=3^{3\cdot 13}=3^{39}\\
9^{20}=3^{2\cdot 20}=3^{40}\\
27^{13}\ \textless \ 9^{20}\\
d)\\9^{13}=3^{2\cdot13}=3^{26}\\
3^{27}\ \textgreater \ 9^{13}
[/tex]