\(B=\left(2021-1\right)\left(2021+1\right).2021=\left(2021^2-1\right).2021=2021^3-2021< A\)

\(B=2020.2021.2022=\left(2021-1\right).2021.\left(2021+1\right)=\left[\left(2021-1\right)\left(2021+1\right)\right].2021=\left(2021^2-2021+2021-1\right).2021=\left(2021^2-1\right).2021=2021^3-2021< 2021^3=A\)

vậy B<A

\(B=2020.2021.2022\\ B=\left(2021-1\right).2021.\left(2021+1\right)\\ B=\left(2021^2-1\right).2021\\ B=2021^3-2021\\ \Rightarrow A>B\)

B=2020.2021.2022B=(2021−1).2021.(2021+1)B=(20212−1).2021B=20213−2021⇒A>B

Vậy a>b

Tham khảo:https://hoc24.vn/cau-hoi/cho-a-20213-va-b-202020212022-khong-tinh-cu-the-cac-gia-tri-cua-a-va-b-hay-so-sanh-a-va-b-ai-lam-giup-mik-voi.3007463332171

có sai ko bạn 

lúc mình làm xiong thấy sai

a>b, mik chắc luôn nhưng ko bt giải thích

A<B

A<B nhé

A < B 

\(A>\left(2021^2-1\right)\cdot2021=\left(2021-1\right)\left(2021+1\right)\cdot2021=B\)

\(A=2021^3=2021\cdot2021^2>2021\left(2021^2-1\right)=2021\left(2021\cdot2021-2021+2021-1\right)=2021\cdot\left(2021+1\right)\left(2021-1\right)=2021\cdot2022\cdot2020=B\)

\(B=2020.2021.2022=\left(2021-1\right).2021.\left(2021+1\right)=\left[\left(2021-1\right)\left(\left(2021+1\right)\right)\right].2011=\left(2021^2-1\right).2021=2021^3-2021< 2021^3=A\)

B = 2020.2021.2022

B = (2021 - 1).(2021 + 1).2021

B = (2021.2021 + 2021 - 2021 - 1).2021

B = (2021²⁰²¹-1).2021

B = 2021³ - 2021

Vậy A > B

\(A>B\)

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