Răspuns:
Explicație pas cu pas:
2020^2 - 2020 - 2019 = 2020*(2020 - 1) - 2019 = 2020*2019 - 2019 =
2019*(2020 - 1) = 2019*2019 = 2019^2 patrat perfect
2019^2, deci patrat perfect.
2020^2-2020-2019 =
2020(2020 - 1) - 2019 =
2020*2019 - 2019 =
2019(2020 - 1) =
2019*2019 =
2019^2, deci patratul perfect al lui 2019.
