Question

分解因式:4x^2-31x+1542 x^5+x+1 x^3+5x^2+3x-9

Answer 1

x^5+x+1

＝x^5-x^2+x^2+x+1

=x^2(x^3-1)+(x^2+x+1)

=x^2*(x-1)(x^2+x+1)+(x^2+x+1)

=(x^2+x+1)(x^3-x^2+1)

x^3+5x^2+3x-9

=(x^3-1)+(5x^2+3x-8)

=(x-1)(x^2+x+1)+(5x+8)(x-1)

=(x-1)(x^2+x+1+5x+8)

=(x-1)(x^2+6x+9)

=(x-1)(x+3)^2