a)\(x^8+x^4+1\)
\(=\left(x^8+2x^4+1\right)-x^4\)
\(=\left(x^4+1\right)^2-x^4\)
\(=\left(x^4-x^2+1\right)\left(x^4+x^2+1\right)\)
\(=\left(x^4-x^2+1\right)\left(x^2-x+1\right)\left(x^2+x+1\right)\)
b)\(x^{10}+x^5+1\)
\(=\left(x^{10}+x^9+x^8\right)-\left(x^9+x^8+x^7\right)+\left(x^7+x^6+x^5\right)-\left(x^6+x^5+x^4\right)+\left(x^5+x^4+x^3\right)-\left(x^3+x^2+x\right)+\left(x^2+x+1\right)\)
\(=x^8\left(x^2+x+1\right)-x^7\left(x^2+x+1\right)+x^5\left(x^2+x+1\right)-x^4\left(x^2+x+1\right)+x^3\left(x^2+x+1\right)-x\left(x^2+x+1\right)+\left(x^2+x+1\right)\)
\(=\left(x^2+x+1\right)\left(x^8-x^7+x^5-x^4+x^3-x+1\right)\)
a) \(x^8+x^4+1\)
= \(x^8+2x^4-x^4+1\)
= \(\left(x^4+1\right)^2-x^4\)
= \(\left(x^4-x^2+1\right)\left(x^4+x^2+1\right)\)
= \(\left(x^4-x^2+1\right)\left(x^4+2x^2-x^2+1\right)\)
= \(\left(x^4-x^2+1\right)\left[\left(x^2+1\right)^2-x^2\right]\)
= \(\left(x^4-x^2+1\right)\left(x^2+1-x^2\right)\left(x^2+1+x^2\right)\)
= \(\left(x^4-x^2+1\right)\left(2x^2+1\right)\)
b) \(x^{10}+x^5+1\)
= ( x10+x9+x8) - (x9+x8+x7) + (x7+x6+x5) - (x6+x5+x4) + (x5+x4+x3) - (x3+x2+x) + (x2+x+1)
= (x2+x+1)(x8 - x7+x5-x4+x3-x+1)