Question

Phân tích đa thức thành nhân tử

\(x^7+x^5+1\)

Answer 1

x^7+x^5+1

= x^7+x^4+x^3+1

=x^4(x^3+1)+(x^3+1)

=(x^4+1)(x^3+1)

Answer 2

\(x^7+x^5+1\)

\(=x^7-x^4+x^4-x+x^5-x^2+x^2+x+1\)

\(=x^4\left(x^3-1\right)+x\left(x^3-1\right)+x^2\left(x^3-1\right)+x^2+x+1\)

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

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