(ii) (A−B)2=A2−AB−BA+B2≠A2−2AB+B2 in general.(A-B)^2=A^2-AB-BA+B^2\ne A^2-2AB+B^2\ \text{in general.}(A−B)2=A2−AB−BA+B2=A2−2AB+B2 in general.