WARNING: For #10, I made a small error: det(kA) = k^n * det(A), where A is an n-by-n matrix. Thus, where I pulled the 2 out of det(2A), I should have instead pulled out a 4 (=2^2). Thus, the final answer is 4*det(A)^3. SORRY ABOUT THAT!
That said, click here for the solutions.