\(x^4-x^2+2x+2\)

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

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

\(=x^2\left(x^2-2x+2\right)+2x\left(x^2-2x+2\right)+\left(x^2-2x+2\right)\)

\(=\left(x^2-2x+2\right)\left(x^2+2x+1\right)\)

\(=\left(x^2-2x+2\right)\left(x+1\right)^2\)

\(x^4-x^2+2x+2\)

\(=x^2\left(x^2-1\right)+2\left(x+1\right)\)

\(=x^2\left(x-1\right)\left(x+1\right)+2\left(x+1\right)\)

\(=\left(x+1\right)\left[x^2\left(x-1\right)+2\right]\)

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

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

\(x^4-5x^2y^2+4y^4\)

\(=\left(x^2\right)^2-2x^22y^2+\left(2y^2\right)^2-x^2y^2\)

\(=\left(x^2-2y^2\right)^2-\left(xy\right)^2\)

\(=\left(x^2-2y^2-xy\right)\left(x^2-2y^2+xy\right)\)

       \(x^4+2002x^2-2001x+2002\)

\(=x^4+2002x^2+x-2002x+2002\)

\(=\left(x^4+x\right)+\left(2002x^2-2002x+2002\right)\)

\(=x\left(x^3+1\right)+2002\left(x^2-x+1\right)\)

\(=x\left(x+1\right)\left(x^2-x+1\right)+2002\left(x^2-x+1\right)\)

\(=\left(x^2-x+1\right)\left[x\left(x+1\right)+2002\right]\)

\(=\left(x^2-x+1\right)\left(x^2+x+2002\right)\)

\(x^6+x^4+x^2y^2+y^4-y^6\)

\(=\left(x^2\right)^3-\left(y^2\right)^3+\left(x^4+x^2y^2+y^4\right)\)

\(=\left(x^2-y^2\right)\left(x^4+x^2y^2+y^4\right)+\left(x^4+x^2y^2+y^4\right)\)

\(=\left(x^4+x^2y^2+y^4\right)\left(x^2-y^2-1\right)\)

\(=\left(x^2-xy+y^2\right)\left(x^2+xy+y^2\right)\left(x^2-y^2-1\right)\)

x^4+64

=(x^2)^2+8^2+2.x^2.8-2.x^2.8

=(x^2+8)^2-16x^2

=(x^2+8-4x)(x^2+8+4x)

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mk chưa lên lp 8