a)
[tex](\frac{3}{5} ^{7}) ^{5} = (\frac{3}{7})^{40} \\\\(\frac{3}{7})^{40} : (\frac{3}{7}^{17}) = (\frac{3}{7}) ^{40-17} = (\frac{3}{7}) ^{23}[/tex]
b)
[tex][(\frac{5}{9} )^{4}]^{6} : (\frac{5}{9} )^{11} \\\\(\frac{5}{9} )^{24} : (\frac{5}{9} )^{11} \\\\(\frac{5}{9} )^{24-11} = (\frac{5}{9} )^{13}[/tex]
c)
[tex](\frac{2}{5})^{51} : [(\frac{2}{5})^{7}]^{3} =\\\\ (\frac{2}{5})^{51} : (\frac{2}{5})^{21}=\\\\(\frac{2}{5})^{51-21} = (\frac{2}{5})^{30}[/tex]
