[tex]\frac{1999.2001-1}{1998.1999.2000}.\frac{7}{5}[/tex]
Giúp mk nhé ( mk sẽ like)
{(1999x2001-1)/(1998+1999x2000)}x7/5
↔{[(1999x(2000+1)-1]/(1998+1999x2000)}...
↔1999x2000+1999-1)/(1998+1999x2000)}...
↔{(1999x2000+1998)/(1998+1999x2000)}x7...
↔1x7/5
→7/5