Question

Phân tích đa thức thành nhân tử:

a. \(2x^2-5x-7\)

b. \(x^3-5x^2+8x-4\)

c. \(x^4+2008x^2+2007x+2008\)

Answer 1

a.\(2x^2-5x-7\)

\(=2x^2-7x+2x-7\)

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

\(=2x\left(x+1\right)-7\left(x+1\right)\)

\(=\left(2x-7\right)\left(x+1\right)\)

Answer 2

a)\(2x^2-5x-7\)

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

\(=\left(x+1\right)\left(2x-7\right)\)

b) \(x^3-5x^2+8x-4\)

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

\(=\left(x-1\right)\left(x^2-4x+4\right)\)

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

c)\(x^4+2008x^2+2007x+2008\)

\(=\left(x^4-x^3+2008x^2\right)+\left(x^3-x^2+2008x\right)+\left(x^2-x+2008\right)\)

\(=\left(x^2-x+2008\right)\left(x^2+x+1\right)\)