Question

Phân tích các đa thức sau thành nhân tử

a) A=2x^2+5xy-3y^2

b) B=x^8-16

Answer 1

a/ \(\left(x+3y\right)\left(2x-y\right)\)

b/ \(\left(x^2+2\right)\left(x^2-2\right)\left(x^2-2x+2\right)\left(x^2+2x+2\right)\)

Answer 2

b/ \(x^8-16=\left(x^4+4\right)\left(x^4-4\right)\)

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

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

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