\ a) (3^2)^3:3^5=3^{2*3}3^6:3^5=3^{6-5}=3
\ b) (\frac{5^4}{5^2})^2=(5^{4-2})^2=(5^2)^2=5^{2*2}=5^4=625
\ c) (\frac{2}{5})^7*2,5^6=(\frac{2}{5})^7*(\frac{5}{2})^6=(\frac{2}{5})^7:(\frac{2}{5})^6=(\frac{2}{5})^{7-6}=\frac{2}{5}
\ d) \frac{4^5}{2^7}*5^3=\frac{(2^2)^5}{2^7}*5^3=\frac{2^{10}}{2^7}*5^3=2^{10-7}*5^3=2^3*5^3=(2*5)^3=10^3=1000
\ e) \frac{9^3*4^4}{6^{10}}=\frac{(3^2)^3*(2^2)^4}{(2*3)^{10}}=\frac{3^6*2^8}{2^{10}*3^{10}}=\frac{1}{2^2*3^4}=\frac{1}{6^2*3^2}=\frac{1}{18^2}
\ f) \frac{0,25^3:0,5^3}{5^3}=0,25^3:0,5^3:5^3=(\frac{1}{4})^3:(\frac{1}{2})^3:5^3=(\frac{1}{4}:\frac{1}{2}:5)^3=(\frac{1}{4}*2*\frac{1}{5})^3=\frac{1}{10^3}=0,001