а) DC + CB1 + B1A1 = -DA -AC -CB -BC1 -CA1 -AA1 +CB1 + B1A1 = -DA -AC -CA1
б) DC + BB1 + C1D1 + DA = -DA -AC -CB -BC1 -AA1 +CA1 +DA = -AC -CB -BC1 +CA1
в) B1A1 - CD1 = CB1 - CD1 = -CB -BD1 = -CB -CB -CC1 = -2CB -CC1
г) DB + AD + CB1 = -CD -BC -AC +CA1 +CB1 = -CD -BC -CC1 +CA1 +CB1 = -DC -BC1 +CA1 +CC1
а) DC + CB1 + B1A1 = -DA -AC -CB -BC1 -CA1 -AA1 +CB1 + B1A1 = -DA -AC -CA1
б) DC + BB1 + C1D1 + DA = -DA -AC -CB -BC1 -AA1 +CA1 +DA = -AC -CB -BC1 +CA1
в) B1A1 - CD1 = CB1 - CD1 = -CB -BD1 = -CB -CB -CC1 = -2CB -CC1
г) DB + AD + CB1 = -CD -BC -AC +CA1 +CB1 = -CD -BC -CC1 +CA1 +CB1 = -DC -BC1 +CA1 +CC1