Question

phân tích đa thức thành nhân tử

a, 4x²-25-(2x-5) (2x+7)

b, x³ +27 +(x +3) (x-9)

c, 4x²y² -(x² + y²- z²)

Answer 1

a) \(4x^2-25-\left(2x-5\right)\left(2x+7\right)\)

\(=\left(2x-5\right)\left(2x+5\right)-\left(2x-5\right)\left(2x+7\right)\)

\(=\left(2x-5\right)\left(2x+5-2x-7\right)\)

\(=-2\left(2x-5\right)\)

b) \(x^3+27+\left(x+3\right)\left(x-9\right)\)

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

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

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

c) \(4x^2y^2-\left(x^2+y^2-z^2\right)\)