Question

Phân tích đa thức thành nhân tử

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

Cần gấp lên ai nhanh mình tick cho

Answer 1

\(x^3-4x^2-12x+27=\left(x^3+27\right)-\left(4x^2+12x\right)\)\(=\left(x+3\right)\left(x^2-3x+9\right)-4x\left(x+3\right)\\ =\left(x+3\right)\left(x^2-3x+9-4x\right)=\left(x+3\right)\left(x^2-7x+9\right)\)

Answer 2

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

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

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

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

Answer 3

\(x^3-4x^2-12x+27\) 

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

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

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