Question

phân tích đa thức thành nhân tử: 2x^4+7x^3-2x^2-13+6

Answer 1

\(2x^4+7x^3-2x^2-13x+6\)

\(=2x^4+6x^3+x^3+3x^2-5x^2-15x+2x+6\)

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

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

\(=\left(2x^3+4x^2-3x^2-6x+x+2\right)\left(x+3\right)\)

\(=\left[2x^2\left(x+2\right)-3x\left(x+2\right)+\left(x+2\right)\right]\left(x+3\right)\)

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

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

\(=\left[2x\left(x-1\right)-\left(x-1\right)\right]\left(x+2\right)\left(x+3\right)\)

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