25^x=2000,80^y=2000,则1/x+1/y=?∵25^x=2000∴(25^x)^y=2000^y即25^xy=2000^y ①∵80^y=2000∴(80^y)^x=2000^x即80^xy=2000^x ②①×②得(25*80)^xy=2000^(x+y)∴2000^xy=2000^(x+y)故xy=x+y∴(x+y)/(xy)=1即1/x+1/...