Arătați ca nr 2018 la 3-2018-2017este pătrat perfect

Răspuns :

2018² - 2018 - 2017 =

= 2018 × ( 2018 - 1 )  - 2017 =

= 2018 × 2017 - 2017 =

= 2017 × ( 2018 - 1 ) =

= 2017 × 2017 =

= 2017² → patrat perfect