1. The problem statement, all variables and given/known data If a 4x4 matrix A with rows v1, v2, v3 and v4 has determinant detA =-2 then then det (v1, 9v2+5v3, 5v2+8v3, v4) =___? 2. Relevant equations 3. The attempt at a solution Ok, so I think it should be -18 (since 9 x -2). I mean the determinant should not change when adding columns to each other, however multiplying should have an effect, but I am not quite sure what happened to the v3, like do I multiply the determinant by 8, or 5, or none?