a)
2525/3535=5/7
505050/707070=5/7
vì 5/7 =5/7
=> 2525/3535=505050/707070
b)
200520052005/200720072007=2005/2007
vì 2005/2006>2005/2007
nên 2005/2006>200520052005/200720072007
a) Ta có: 2525/3535 = 5/7
505050/707070 = 5/7
Vì 5/7 = 5/7 nên 2525/3535 = 505050/707070
b) Ta có: 2005200520/200720072007 = 2005/2007
Vì 2006 < 2007 => 2005/2006 > 2005/2007
Nên 2005/2006 > 200520052005/200720072007