a) Sửa đề
\(x^3-6x^2+9x\)
\(=x\left(x^2-6x+9\right)\)
\(=x\left(x-3\right)^2\)
b) \(x^2-2xy+2x-4y\)
\(=x\left(x-2y\right)+2\left(x-2y\right)\)
\(=\left(x-2y\right)\left(x+2\right)\)
c) \(x\left(x+y\right)-5x-5y\)
\(=x\left(x+y\right)-5\left(x+y\right)\)
\(=\left(x+y\right)\left(x-5\right)\)
d) \(x^2\left(x+1\right)-x\left(x+1\right)\)
\(=x\left(x+1\right)\left(x-1\right)\)