Practicing Success
Practicing Success
CUET Preparation Today
If $A=\begin{bmatrix}x+4,& 2\\3 & 1\end{bmatrix}, B = \begin{bmatrix} x & 2x-1\\2 & 5\end{bmatrix}$ and |AB|= 12 then, the value (s) of x is/are : |
3 4 ±4 ±3 |
±4 |
The correct answer is Option (3) → ±4 $|A|=(x+4)-6=x-2$ $|B|=5x-2(2x-1)=x+2$ so $|AB|=12⇒|A||B|=12$ $(x-2)(x+2)=12⇒x^2-4=12$ $⇒x=±4$ |
