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\(\left(x+1\right)^4-6\left(x+1\right)^2-\left(x^2-2\right)\left(x^2+2\right)\\ =x^4+4x^3+6x^2+4x+1-6x^2-12x-6-x^4+4\\ =4x^3-8x+5\)

12 tháng 11 2017

rút gọn phân thức:

\(\dfrac{\left(-x\right)^5.a^2}{x^2.\left(-a\right)^3}=\dfrac{x^2.\left(-x\right)^3.a^2}{x^2.\left(-a\right).a^2}=\dfrac{-x^3}{-a}=\dfrac{x^3}{a}\)

12 tháng 11 2017

\(\dfrac{\left(-x\right)^5.a^2}{x^2.\left(-a\right)^3}\\ =\dfrac{\left(-x\right)^3x^2.a^2}{x^2.\left(-a\right).a^2}\\ =\dfrac{\left(-x\right)^3}{a}\)

NV
25 tháng 12 2018

\(A-1=\left(x+1\right)\left(x^2+1\right)...\left(x^{256}+1\right)\)

\(\Rightarrow\left(A-1\right)\left(x-1\right)=\left(x-1\right)\left(x+1\right)\left(x^2+1\right)...\left(x^{256}+1\right)\)

\(\Rightarrow\left(A-1\right)\left(x-1\right)=\left(x^2-1\right)\left(x^2+1\right)...\left(x^{256}+1\right)\)

\(\Rightarrow\left(A-1\right)\left(x-1\right)=\left(x^4-1\right)\left(x^4+1\right)...\left(x^{256}+1\right)\)

\(\Rightarrow\left(A-1\right)\left(x-1\right)=\left(x^{256}-1\right)\left(x^{256}+1\right)=x^{512}-1\)

\(\Rightarrow A-1=\dfrac{x^{512}-1}{x-1}\)

\(\Rightarrow A=\dfrac{x^{512}-1}{x-1}+1=\dfrac{x^{512}+x-2}{x-1}\)

\(=\dfrac{\left(x+2\right)^2}{x}\cdot\dfrac{x+2-x^2}{x+2}-\dfrac{x^2+6x+4}{x}\)

\(=\dfrac{\left(x+2\right)\left(-x^2+x+2\right)-x^2-6x-4}{x}\)

\(=\dfrac{-x^3+x^2+2x-2x^2+2x+4-x^2-6x-4}{x}\)

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