\(=\dfrac{\left(x-2\right)\left(x+1\right)}{-\left(x-2\right)\left(x+2\right)}=\dfrac{-x-1}{x+2}\)

\(x\left(x+y\right)\left(x^2+y^2\right)\left(x^4+y^4\right)\left(x^8+y^8\right)\left(x-y\right)+xy^{16}\\ =x\left(x+y\right)\left(x-y\right)\left(x^2+y^2\right)\left(x^4+y^4\right)\left(x^8+y^8\right)+xy^{16}\\ =x\left(x^2-y^2\right)\left(x^2+y^2\right)\left(x^4+y^4\right)\left(x^8+y^8\right)+xy^{16}\\ =x\left(x^4-y^4\right)\left(x^4+y^4\right)\left(x^8+y^8\right)+xy^{16}\\ =x\left(x^8-y^8\right)\left(x^8+y^8\right)+xy^{16}\\ =x\left(x^{16}-y^{16}\right)+xy^{16}\\ =x^{17}-xy^{16}+xy^{16}\\ =x^{17}\)

\(x\left(x+y\right)\left(x^2+y^2\right)\left(x^4+y^4\right)\left(x^8+y^8\right)\left(x-y\right)+xy^{16}\)

\(=x\left(x-y\right)\left(x+y\right)\left(x^2+y^2\right)\left(x^4+y^4\right)\left(x^8+y^8\right)+xy^{16}\)

\(=x\left(x^2-y^2\right)\left(x^2+y^2\right)\left(x^4+y^4\right)\left(x^8+y^8\right)+xy^{16}\)

\(=x\left(x^4-y^4\right)\left(x^4+y^4\right)\left(x^8+y^8\right)+xy^{16}\)

\(=x\left(x^8-y^8\right)\left(x^8+y^8\right)+xy^{16}\)

\(=x\left(x^{16}-y^{16}\right)+xy^{16}\)

\(=x^{17}-xy^{16}+xy^{16}\)

\(=x^{17}\)

\(x(x+y)(x^2+y^2)(x^4+y^4)(x^8+y^8)(x-y)+xy^{16}\\=x(x-y)(x+y)(x^2+y^2)(x^4+y^4)(x^8+y^8)+xy^{16}\\=x(x^2-y^2)(x^2+y^2)(x^4+y^4)(x^8+y^8)+xy^{16}\\=x(x^4-y^4)(x^4+y^4)(x^8+y^8)+xy^{16}\\=x(x^8-y^8)(x^8+y^8)+xy^{16}\\=x(x^{16}-y^{16})+xy^{16}\\=x^{17}-xy^{16}+xy^{16}\\=x^{17}\\Toru\)

Câu này  cô làm rồi em nhá, em xem phần câu hỏi của tôi ý

Q = \(\dfrac{1+x^4+x^8+...+x^{2020}}{1+x^2+...+x^{2022}}\)

Đặt A = 1 + \(x^4\) + \(x^8\) +...+ \(x^{2020}\)

Đặt B = 1 + \(x^2\) + ...+ \(x^{2022}\)

Thì Q = \(\dfrac{A}{B}\) 

A              = 1 + \(x^4\) + \(x^8\) + ...+ \(x^{2020}\)

A.\(x^4\)         =       \(x^4\) + \(x^8\) +....+ \(x^{2020}\) + \(x^{2024}\)

A.\(x^4\) - A    = \(x^{2024}\) - 1

A              = \(\dfrac{x^{2024}-1}{x^4-1}\) 

B             = 1 + \(x^2\) + \(x^4\) +...+ \(x^{2020}\) + \(x^{2022}\) 

B.\(x^2\)        =       \(x^2\) + \(x^4\) +...+ \(x^{2020}\) + \(x^{2022}\) + \(x^{2024}\)

B\(x^2\) - B   =       \(x^{2024}\) - 1

B             = \(\dfrac{x^{2024}-1}{x^2-1}\)

Q = \(\dfrac{\dfrac{x^{2024}-1}{x^4-1}}{\dfrac{x^{2024}-1}{x^2-1}}\)

Q  = \(\dfrac{x^{2024}-1}{x^4-1}\) \(\times\)\(\dfrac{x^2-1}{x^{2024}-1}\)

Q  = \(\dfrac{1}{x^2+1}\)

a kham khảo nha , e nhờ a e lm chứ ko phải e lm nha ! 

\(\left(x-2\right)\left(\frac{3}{x}+2-\frac{5}{2x}-4+\frac{8}{x^2}-4\right)\)

\(\left(x-2\right)\left[\left(\frac{3}{x}-\frac{5}{2x}\right)-6+\frac{8}{x^2}\right]\)

\(\left(x-2\right)\left(\frac{1}{2x}-6+\frac{8}{x^2}\right)\)

\(\left(x-2\right)\left(\frac{3}{x+2}-\frac{5}{2x-4}+\frac{8}{x^2-4}\right)\)

\(=\left(x-2\right)\left[\frac{3}{x+2}-\frac{5}{2\left(x-2\right)}+\frac{8}{\left(x-2\right)\left(x+2\right)}\right]\)

\(=\left(x-2\right)\left[\frac{3.2\left(x-2\right)}{2\left(x-2\right)\left(x+2\right)}-\frac{5\left(x+2\right)}{2\left(x-2\right)\left(x+2\right)}+\frac{8.2}{2\left(x-2\right)\left(x+2\right)}\right]\)

\(=\left(x-2\right)\left[\frac{6\left(x-2\right)}{2\left(x-2\right)\left(x+2\right)}-\frac{5\left(x+2\right)}{2\left(x-2\right)\left(x+2\right)}+\frac{16}{2\left(x-2\right)\left(x+2\right)}\right]\)

\(=\left(x-2\right)\left[\frac{6\left(x-2\right)-5\left(x+2\right)+16}{2\left(x-2\right)\left(x+2\right)}\right]\)

\(=\frac{\left(x-2\right)\left(x-6\right)}{2\left(x-2\right)\left(x+2\right)}\)

\(=\frac{x-6}{2\left(x+2\right)}\)

\(\dfrac{x^3+3x^2-2}{x^3+3x+4}\)

\(=\dfrac{x^3+x^2+2x^2+2x-2x-2}{x^3-x+4x+4}\)

\(=\dfrac{\left(x+1\right)\left(x^2+2x-2\right)}{\left(x+1\right)\left(x^2-x+4\right)}\)

\(=\dfrac{x^2+2x-2}{x^2-x+4}\)