Question

Tính giá trị của biểu thức:

M = x⁵ – 2022x⁴ + 2022x³ – 2022x² + 2022x – 2921

tại x = 2021.

Answer 1

\(M=\left(x^5-2021x^4\right)-\left(x^4-2021x^3\right)+\left(x^3-2021X^2\right)-\left(x^2-2021x\right)+\left(x-2021\right)-900=-900\)

Answer 2

Ta có: x=2021

nên x+1=2022

Ta có: \(M=x^5-2022x^4+2022x^3-2022x^2+2022x-2921\)

\(=x^5-x^4\left(x+1\right)+x^3\left(x+1\right)-x^2\left(x+1\right)+x\left(x+1\right)-2921\)

\(=x^5-x^5-x^4+x^4+x^3-x^3-x^2+x^2+x-2921\)

\(=x-2921=-900\)