Express the total-spin states ∣1,1⟩ and ∣1,−1⟩ (with respect to the z -axis, as usual) of a system made of two spin- 2 1 ​ particles in terms of the product states ∣+x,+x⟩ , ∣+x,−x⟩,∣−x,+x⟩ , and ∣−x,−x⟩