Question

phân tích đa thức thành nhân tử  x³-12x-4x²+27

Answer 1

x³-12x-4x²+27

=(x³+27)-(12x+4x²)

=(x+3)(x²-3x+9)-4x(x+3)

=(x+3)(x²-3x+9-4x)

=(x+3)(x²-7x+9)

Answer 2

\(x^3-12x-4x^2+27\)

\(=x^3+3x^2-7x^2-21x+9x+27\)

\(=x^2\left(x+3\right)-7x\left(x+3\right)+9\left(x+3\right)\)

\(=\left(x+3\right)\left(x^2-7x+9\right)\)