Question

không tính. hãy so sánh a= 2013 x 2013 và b= 2009 x 2017

Answer 1

Ta có `:`

`a = 2013 xx 2013`

`= 2013 xx ( 2017-4)`

`=2013xx2017-4xx2013`

`=(2009+4)xx2017-4xx2013`

`=2017xx2009+4xx2017-4xx2013`

`= 2017xx2009 +4xx(2017-2013)`

`= 2017xx2009 + 4xx4`

`= 2017xx2009+16`

Do `2017xx2009+16` `> 2017 xx 2009` nên `a > b` 

 

 

Answer 2

\(b=2009\cdot2017=2013^2-16< 2013^2=a\)

Answer 3

a,2013x2013

=(2009+4)x2013

=2009x2013+8052

b,2009x2017

=2009x(2013+4)

=2019x2013+8036

Vì 2019x2013+8052>2019x2013+8052 hay A>B