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