If … is the inverse of a 3 × 3 matrix A, then the sum of all values of … for which det(A) + 1 = 0, is :

Matrices and Determinants

JEE Main 2019 · 12 Apr, Morning shift · Q4448

MathematicsMedium244×since 2002Q4448

B = \left[ {\matrix{ 5 & {2\alpha } & 1 \cr 0 & 2 & 1 \cr \alpha & 3 & { - 1} \cr } } \right]

is the inverse of a 3 × 3 matrix A, then the sum of all values of

\alpha

for which det(A) + 1 = 0, is :

JEE Main 2019 · 12 Apr, Morning shift · Q4448

MathematicsMedium244×since 2002Q4448

B = \left[ {\matrix{ 5 & {2\alpha } & 1 \cr 0 & 2 & 1 \cr \alpha & 3 & { - 1} \cr } } \right]

is the inverse of a 3 × 3 matrix A, then the sum of all values of

\alpha

for which det(A) + 1 = 0, is :