Determine which of the following formulas hold for all invertible ×n×n matrices A and B. 1. =AB=BA 2. +A+B is invertible 3. (+)2=2+2+2(A+B)2=A2+B2+2AB 4. (+)(+−1)=2++−1(I+A)(I+A−1)=2I+A+A−1 5. (−)(+)=−2(I−A)(I+A)=I−A2 6. ()−1=−1−1(AB)−1=A−1B−1 7. 3A3 is invertible 8. (−1)3=3−1(ABA−1)3=AB3A−1 9. −1=ABA−1=B 10. (+)(−)=2−2