2017.2017=(2018-1).2017=2018.2017-2017 (1)
2018.2016=2018.(2017-1)=2018.2017-2018 (2)
từ (1) và (2) suy ra 2017.2017 > 2018.2017
A=2017^2
B=(2017+1)(2017-1)
=2017^2-1^2
VÌ 2017^2 >2017^2-1^2
VẬY A >B
A = 2017 . ( 2016 + 1 )
A = 2017 . 2016 + 2017
B = ( 2017 + 1 ) . 2016
B = 2016 . 2017 + 2016
Suy ra :
A > B