Răspuns:
Explicație pas cu pas:
a)
2019 + 2020*2019 - 2021*2018 = 2019*(1 + 2020) - 2021*2018
= 2019*2021 - 2021*2018 = 2021*(2019 - 2018) = 2021*1 = 2021
b)
2^2021 - 2^2020 - 2^2019 - 2^2018 = 2^2018*(2^3 - 2^2 - 2 - 1)
= 2^2018*(8 - 4 - 2 - 1) = 2^2018
c)
(-2)^2020 = 2^2020
(-2)^2019 = -2^2019
(-2)^2018 = 2^2018
2^2020 - 2^2019 = 2^2019*(2 - 1) = 2^2019
I2^2019I : 2^2018 = 2^2019 : 2^2018 = 2
