A=(2015+1).2017 B= (2016+1).2016 A=2016X2017 B=2017X2016 VẬY A=B
A = 2015.2017 và B = 2016 . 2016
A = 2015 . 2017
A = 2015 . ( 2016 + 1 )
A = 2015 . 2016 + 2015
B = 2016 . 2016
B = ( 2015 + 1 ) . 2016
B = 2015 . 2016 + 2016
Mà 2015. 2016 + 2015 < 2015 . 2016 + 2016
=> A < B