Thematrix[]21A41??=??-??isdecomposedintoaproductofalowertriangularmatrix[]Landanuppertriangularmatrix[]U.Theproperlydecomposed[]Land[]Umatricesrespectivelyare(a)1041????-??and1041????-??(b)2041????-??and1101??????(c)1041??????and2101????-??(d)2043????-??and10.501??????