Let X, X′ , Y, Y ′ be sets. Let × denote the Cartesian product of sets. Show that X × Y − X ′ × Y ′ = ((X ∩ X ′ ) × (Y − Y ′ )) ∪ ((X − X ′ ) × Y ) . Solution:(x, y) ∈ LHS ⇔x ∈ X ∧ y ∈ Y ∧ ¬(x ∈ X′∧