If A is a 4x4 matrix...

and det(A) = -3, then:

det(2A) = ?
det(A^T) = ?

Since A is 4 x 4,
det(2A) = 2^4 * |A| = 16 * -3 = -48.
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Since transposition does not affect the determinant,
det(A^T) = det(A) = -3.

I hope this helps!