Question

Answer 1

a) P=(x+1)(x²-x+1)+x-(x-1)(x²+x+1) =x³+1+x-(x³-1)+2020=x³+1+x-x³+1+2020=x+2022

Thay x= -2021 vào biểu thức P ta có:

x+2022=-2021+2022=1

Answer 2

Lời giải:

a.

\(P=(x^3+1)+x-(x^3-1)+2020\)

\(=x+2022=-2021+2022=1\)

 b.

\(Q=64x^3-80x-(64x^3+1)=-80x-1=-80.\frac{1}{5}-1=-17\)

Answer 3

a: Ta có: \(P=\left(x+1\right)\left(x^2-x+1\right)+x-\left(x-1\right)\left(x^2+x+1\right)+2020\)

\(=x^3+1+x-x^3+1+2020\)

\(=x+2022=1\)

b: Ta có: \(Q=16x\left(4x^2-5\right)-\left(4x+1\right)\left(16x^2-4x+1\right)\)

\(=64x^3-80x-64x^3-1\)

\(=-16-1=-17\)