几道分解因式的题目x^3-9x^2+27x-27a^4+4x^3+2x^2-5x-6
1个回答

(1)x^3-9x^2+27x-27

=x^3-27-(9x^2-27x)

=(x-3)*(x^2+3x+9)-9x(x-3)

=(x-3)(x^2+3x+9-9x)

=(x-3)(x^2-6x+9)

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

=(x-3)^3

(2)a^4+4

=(a^4+2a^3+2a^2)-(2a^3+4a^2+4a)+(2a^2+4a+4)

=a^2(a^2+2a+2)-2a(a^2+2a+2)+2(a^2+2a+2)

=(a^2+2a+2)(a^2-2a+2)

(3)x³+2x²-5x-6

=(x³+x²)+(x²-5x-6)

=x²(x+1)+(x-6)(x+1)

=(x²+x-6)(x+1)

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