Remember the formulas | a t | = | a |, | a t | = | a |, | aa | = a n | a |.

| a (-1) | =1| a |, AA*=|A|E and so on.

And | a * | = | a | (n- 1)

So we get | a t a | =| a | 2 = 9.

|2A^- 1|=2^3 /|A|=8/3

||A|A*|=|3A*|=3^3 |A|^2=243

A*(A*)*=|A*|E, so | a * (a *) * | = || a * | e | = | 9e | = 9 3 = 243.

And |(A*)*|=243/|A*|=27.

|3a^- 1 -2a*|=|3a^- 1 -2×3a^- 1|=|-3a^- 1|=(-3)^3/| a | =-9