1
COMEDK 2024 Evening Shift
+1
-0

$$\text { If } A=\left[\begin{array}{cc} 5 a & -b \\ 3 & 2 \end{array}\right] \text { and } A \operatorname{adj} A=A A^t \text {, then } 5 a+b \text { is equal to }$$

A
5
B
$$-$$1
C
4
D
13
2
COMEDK 2024 Evening Shift
+1
-0

If the matrix $A$ is such that $$A\left(\begin{array}{cc}-1 & 2 \\ 3 & 1\end{array}\right)=\left(\begin{array}{cc}-4 & 1 \\ 7 & 7\end{array}\right)$$ then $$A$$ is equal to

A
$$\left(\begin{array}{cc}1 & 1 \\ 2 & -3\end{array}\right)$$
B
$$\left(\begin{array}{cc}-1 & 1 \\ 2 & 3\end{array}\right)$$
C
$$\left(\begin{array}{cc}1 & 1 \\ -2 & 3\end{array}\right)$$
D
$$\left(\begin{array}{cc}1 & -1 \\ 2 & 3\end{array}\right)$$
3
COMEDK 2024 Evening Shift
+1
-0

If $$A=\left[\begin{array}{ccc}0 & x & 16 \\ x & 5 & 7 \\ 0 & 9 & x\end{array}\right]$$ is a singular matrix then $$x$$ is equal to

A
$$-12$$
B
21
C
$$-144$$
D
144
4
COMEDK 2024 Morning Shift
+1
-0

$$\text { If } P=\left[\begin{array}{lll} 1 & \alpha & 3 \\ 1 & 3 & 3 \\ 2 & 4 & 4 \end{array}\right] \text { is the adjoint of a } 3 \times 3 \text { matrix } A \text { and }|A|=4 \text { then } \alpha \text { is equal to }$$

A
11
B
4
C
0
D
5
EXAM MAP
Medical
NEET