Question

Phân tích các đa thức sau thành nhân tử

\(x^2-2x-4y^2-4y\)

 

Answer 1

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

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

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

Answer 2

\(x^2-2x-4y^2-4y\)

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

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

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

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

Answer 3

\(x^2-2x-4y^2-4y\)

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

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