Bài 3: Những hằng đẳng thức đáng nhớ

H24

Tính nhanh:

a) A=\(\frac{2020^3+1}{2020^2-2019}\) b)B=\(\frac{2020^3-1}{2020^2+2021}\)

LN
22 tháng 8 2019 lúc 20:44

a)

\(A=\frac{2020^3+1}{2020-2019}=\frac{\left(2020+1\right)\left(2020^2-2020+1\right)}{2020-2020+1}\) \(=2020+1=2021\)

b)

B = \(\frac{2020^3-1}{2020^2+2021}=\frac{\left(2020-1\right)\left(2020^2+2020+1\right)}{2020^2+2020+1}\) \(=2020-1=2019\)

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H24
22 tháng 8 2019 lúc 21:01

a. \(A=\frac{2020^3+1}{2020^2-2019}=\frac{\left(2020+1\right)\left(2020^2-2020+1\right)}{2020^2-2020+1}=2020+1=2021\)

b. \(B=\frac{2020^3-1}{2020^2+2021}=\frac{\left(2020-1\right)\left(2020^2+2020+1\right)}{2020^2+2020+1}=2020-1=2019\)

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