\(x^3+2x^2+x=x\left(x^2+2x+1\right)=x\left(x+1\right)^2\)
\(5x^2+10x-5y^2+5==5\left(x^2+2x+1-y^2\right)=5\left[\left(x+1\right)^2-y^2\right]=5\left(x+1-y\right)\left(x+1+y\right)\)
\(4x^3-8x^2y+4xy^2=4x\left(x^2-2xy+y^2\right)=4x\left(x-y\right)^2\)
\(x^3+9x^2y-xy=x\left(x^2+9xy-y\right)\)
a) \(x^3+2x^2+x=x\left(x^2+2x+1\right)=x\left(x+1\right)^2\)
b) \(-5x^2+10x-5y+5=-5\left(x^2-2x+y-1\right)\)
c)\(4x^3-8x^2y+4xy^2=4x\left(x^2-2xy+y^2\right)=4x\left(x-y\right)^2\)
d) \(x^3+9x^2y-xy=x\left(x^2+9xy-y\right)\)