Question

a) \(3x^2y-6xy\)

b)\(x^2-y^2+6x+9\)

Answer 1

a) \(3x^2y-6xy\)  

\(=3xy\left(x-2\right)\)

b) \(x^2-y^2+6x+9\)

\(=\left(x^2-6x+9\right)-y^2\)

\(=\left(x-3\right)^2-y^2\)

\(=\left(x-3-y\right)\left(x-3+y\right)\)

Answer 2

a) Ta có: \(3x^2y-6xy\)

\(=3xy\cdot x-3xy\cdot2\)

\(=3xy\left(x-2\right)\)

b) Ta có: \(x^2-y^2+6x+9\)

\(=\left(x^2+6x+9\right)-y^2\)

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

\(=\left(x+3+y\right)\left(x+3-y\right)\)