Tính nhanh: A = $\frac{2020^{3}+1}{2020^{2}-2019}$ B = $\frac{2020^{3}-1}{2020^{2}+2021}$

Đáp án:

$A=2021$

$B=2019$

Giải thích các bước giải:

$A=\dfrac{2020^3+1}{2020^2-2019}$

$=\dfrac{(2020+1)(2020^2-2020+1)}{2020^2-2019}$

$=\dfrac{2021.(2020^2-2019)}{2020^2-2019}$

$=2021$

$B=\dfrac{2020^3-1}{2020^2+2021}$

$=\dfrac{(2020-1)(2020^2+2020+1}{2020^2+2021}$

$=\dfrac{2019.(2020^2+2021)}{2020^2+2021}$

$=2019$