Question

A= 2009 x 2011 va B= 2010^2

Answer 1

ta có 2010^2=2010x2010

ta có 2009x2011=2009x(2010+1)=2009x2010+2009

        2010x2010=(2009+1)x2010=2009x2010+2010

Mà 2009<2010

=>2009x2010+2009<2009x2010+2010

=>2009x2011<2010^2

=>A<B

Answer 2

2010² = 2010 x 2010

Vì 2009 x 2010 < 2010 x 2010 => 2009 x 2010 < 2010² => A < B

Answer 3

A = 2009 x 2011

   = 2009 x (2010 + 1)

   = 2009 x 2010 + 2009

 

B = 2010²

   = 2010 x 2010

   = (2009 + 1) x 2010

   = 2009 x 2010 + 2010 

Vì 2009 x 2010 + 2010 > 2009 x 2010 + 2009 nên B > A 

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