x^10+x^5+1
=x10-x+x5-x2+x2+x+1
=x.(x9-1)+x2.(x3-1)+(x2+x+1)
=x.(x3-1)(x3+1)+x2(x3-1)+(x2-x+1)
=x.(x-1)(x2+x+1)(x3+1)+x2(x-1)(x2+x+1)+(x2+x+1)
=(x2+x+1)[x.(x-1)(x3+1)+x2(x-1)+1]
=(x2+x+1)(x5+x2-x4-x+x3-x2+1)
=(x2+x+1)(x5-x4+x3-x+1)
x^10+x^5+1
=x10-x+x5-x2+x2-x+1
=x.(x9-1)+x2.(x3-1)+(x2+x+1)
=x.(x3-1)(x3+1)+x2(x3-1)+(x2-x+1)
=x.(x-1)(x2+x+1)(x3+1)+x2(x-1)(x2+x+1)+(x2+x+1)
=(x2+x+1)[x.(x-1)(x3+1)+x2(x-1)+1]
=(x2+x+1)(x5+x2-x4-x+x3-x2+1)
=(x2+x+1)(x5-x4+x3-x+1)
ta có:
A= x^10 + x^5 + 1
A= (x^10 -x) + (x^5-x²) + (x²+x+1)
A= x.(x³ -1).(x^6+x³+1) + x².(x³-1) + (x²+x+1)
A= x.(x -1).(x²+x+1).(x^6+x³+1) + x².(x-1).(x²+x+1) + (x²+x+1)
A= (x²+x+1).[x.(x-1).(x^6+x³+1) + x².(x²+x+1) +1]
có cách tắt hơn nè L: ( cách cô giáo mk lm )
\(x^{10}+x^5+1\)
\(=\left(x^{10}-x\right)+\left(x^5-x^2\right)+\left(x^2+x+1\right)\)
\(=x.\left[\left(x^3\right)^3-1\right]+x^2.\left(x^3-1\right)+\left(x^2+x+1\right)\)
\(=x\left(x^3-1\right).\left(x^6+x^3+1\right)+x^2.\left(x^3-1\right)+\left(x^2+x+1\right)\)
\(=\left[x.\left(x-1\right).\left(x^6+x^3+1\right)+x^2+1\right].\left(x^2+x+1\right)\)
