For what value of x will |\( 8{ A }^{ T } \)| =0 if A = \(\begin{bmatrix}2 & 1\\x^2 & 8 \end{bmatrix}\)?
Answer & explanation
Correct answer: option 3
Given that |8\( { A }^{ T } \)| =0
Also, |\(8 { A }^{ T } \)| = \( { 8 }^{ 2 } \) |\( { A }^{ T } \)|
= \( { 8 }^{ 2 } \) |A |
= 64|A|
Because |\( { A }^{ T } \) = |A |
So, 0 =64 |A|
|A| = 0
\( { x }^{ 2 } \)-16 = 0
\( { x }^{ 2 } \) = 16
x= 4 and -4