A^3＋A^2-A-2E=0(A-E)(A^2+3A +2E) =0(A-E)(A+E)(A+2E)=0A=E or -E or -2EA-E = 0 or -2E or -3E(A-E)^(-1) = (-3E)^(-1) or (-4E)^(-1) =-(1/3)E or -(1/4)E
