Consider the block matrix M=(AB0C)M = \begin{pmatrix} A & B \\ 0 & C \end{pmatrix}M=(A0BC) where AAA and CCC are square matrices. What is det(M)\det(M)det(M)?
det(A)⋅det(C)−det(B)\det(A) \cdot \det(C) - \det(B)det(A)⋅det(C)−det(B)
det(A)\det(A)det(A)
det(A)+det(C)\det(A) + \det(C)det(A)+det(C)
det(A)⋅det(C)\det(A) \cdot \det(C)det(A)⋅det(C)