m: \(=\left(x-3\right)\left(x^2+3x+9\right)+x\left(x-3\right)=\left(x-3\right)\left(x^2+4x+9\right)\)
n: \(=\left(x-y\right)^2-\left(2z\right)^2=\left(x-y-2z\right)\left(x-y+2z\right)\)
p: \(=x^2\left(x+1\right)+8\left(x+1\right)=\left(x+1\right)\left(x^2+8\right)\)