Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Determinants

Question:

For what value of x will |\( -2 { A }^{ T } \)| =20 if A = \(\begin{bmatrix}x & 4\\3 & 1 \end{bmatrix}\)?

Options:

17

-1

0

2

Correct Answer:

17

Explanation:

Given that |-2\( { A }^{ T } \)| =20

Also,   \((-2)^{ 2 } \) |\( { A }^{ T } \)|

4|\( { A }^{ T } \)| = 20

Because |\( { A }^{ T }| \) = |A |

So, 20 = 4|A|

20= 4(x-12)

5=x-12

17=x