7^5n*5^(n+1)/35^(n-1)-?
(7^5n*5^(n+1))/35^(n-1)=(7^5n*5^(n+1))/(7^(n-1)*5^(n-1))=7^(5n-n+1)*5^(n+1-n+1)=7^(4n+1)*5^2=25*7*7^4n=175*7^4n