Câu 7: Không tính kết quả, hãy so sánh A và B biết:
A = 2008 × 2008 ; B = 2007 × 2009
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TL :
A > B
HT
nha bn
A= 2008 x 2008
= 2008 x ( 2007+1)
= 2008 x 2007 + 2008
B= 2007 x 2009
= 2007 x ( 2008+1)
= 2007 x 2008 + 2007
Vì 2008>2007 => 2008 x 2007 + 2008 > 2007 x 2008 + 2007
Hay A > B
Vậy A > B
_HT_