<<VilGebra`

A={{x,0,-1+(x^3)},{0,1,x},{1,1,(x^2)}};
InversaSP[A]

A={{x,0,-1+(x^3)},{0,1,x},{1,1,(x^2)}};
InversaCP[A]

{{x,0,-1+(x^3),1,0,0},{0,1,x,0,1,0},{1,1,(x^2),0,0,1}}/.x->0//MatrixForm
InversaSP[Take[%,All,3]]

{{1,0,(((-1+x) (1+x+(x^2)))/x),(1/x),0,0},{0,1,x,0,1,0},{0,0,-(((-1+x) (1+x))/x),-(1/x),-1,1}}/.x->-1//MatrixForm
InversaSP[Take[%,All,3]]
{{1,0,(((-1+x) (1+x+(x^2)))/x),(1/x),0,0},{0,1,x,0,1,0},{0,0,-(((-1+x) (1+x))/x),-(1/x),-1,1}}/.x->1//MatrixForm
InversaSP[Take[%,All,3]]