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Linear AlgebraSuperchallengeDeterminants & Inverses

Determinants & Inverses · Superchallenge problem

Let JJ be the 4×44\times4 matrix with every entry 11. A 4×44\times4 matrix AA satisfies det⁡A=3\det A = 3 and det⁡(A+J)=7\det(A + J) = 7. Find det⁡(A+5J)\det(A + 5J).