a) [tex]\frac{9}{4}\cdot\frac{16}{18}:\frac{13}{6}=\frac{144}{72}\cdot\frac{6}{13}=2\cdot \frac{6}{13}=\frac{12}{13}[/tex]
b)[tex](\frac{4}{5})^{13}:(\frac{4}{5})^{12}=\frac{4}{5}[/tex]
c)
[tex]\{[(\frac{2}{3})^{1010}]^2\cdot(\frac{2}{3})^{20}-(\frac{2}{3})^{2000}\}\cdot(\frac{2}{3})^{4000}= [(\frac{2}{3})^{2040}-(\frac{2}{3})^{2000}]\cdot(\frac{2}{3})^{4000}=\\
(\frac{2}{3})^{6000}((\frac{2}{3})^{40}-1)[/tex]
