det(AB) = det(A) * det(B) = -3
det(-2A) = (-2)^2 * det(A) = -4
det(A^T) = det(A) = -1
det(B^-1) = 1/det(B) = 1/3
det(B^4) = det(B)^4 = 81
x = 23.78
step-by-step explanation: