Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Determinants

Question:

If A = \(\begin{bmatrix}3 & 3\\6 & 8 \end{bmatrix}\), then what can be said about 24\( { A }^{ -1 } \)?

Options:

24\( { A }^{ -1 } \) = 4 (adj A)

24\( { A }^{ -1 } \) = 3 (adj A)

24\( { A }^{ -1 } \) = 24 (adj A)

None of these

Correct Answer:

24\( { A }^{ -1 } \) = 4 (adj A)

Explanation:

\( { A }^{ -1 } \) =\(\frac{adj A}{|A|}\)

But |A| = 6

So, \( { A }^{ -1 } \) =\(\frac{adj A}{6}\)

     24 \( { A }^{ -1 } \) = 24 \(\frac{adj A}{6}\)

                                     = 4 (adj A)