Matrices and Determinants - Jamb Mathematics Past Questions and Answers

Question 36:

• JAMB 2011

The inverse of matrix N = \(\begin{vmatrix} 2 & 3 \\
1 & 4\end{vmatrix}\) is

A. \(\frac{1}{5}\) \(\begin{vmatrix} 2 & 1 \\ 3 & 4\end{vmatrix}\)
B. \(\frac{1}{5}\) \(\begin{vmatrix} 4 & -3 \\ -1 & 2\end{vmatrix}\)
C. \(\frac{1}{5}\) \(\begin{vmatrix} 2 & -1 \\ -3 & 4\end{vmatrix}\)
D. \(\frac{1}{5}\) \(\begin{vmatrix} 4 & 3 \\ 1 & 2\end{vmatrix}\)

Question 37:

• JAMB 2012

If \(\begin{vmatrix} 5 & 3 \\ x & 2 \end{vmatrix}\) = \(\begin{vmatrix} 3 & 5 \\ 4 & 5 \end{vmatrix}\), find the value of x

A. 3
B. 4
C. 5
D. 7

Question 38:

• JAMB 2012

Given that I₃ is a unit matrix of order 3, find |I₃|

A. -1
B. O
C. 1
D. 2

Question 39:

• JAMB 2013

If P = \(\begin{pmatrix} 5 & 3 \\ 2 & 1 \end{pmatrix}\) and Q = \(\begin{pmatrix} 4 & 2 \\ 3 & 5 \end{pmatrix}\), find 2P + Q

A. \(\begin{vmatrix} 7 & 7 \\ 14 & 8 \end{vmatrix}\)
B. \(\begin{vmatrix} 14 & 8 \\ 7 & 7 \end{vmatrix}\)
C. \(\begin{vmatrix} 7 & 7 \\ 8 & 14 \end{vmatrix}\)
D. \(\begin{vmatrix} 8 & 14 \\ 7 & 7 \end{vmatrix}\)

Question 40:

• JAMB 2013

Find the inverse \(\begin{pmatrix} 5 & 3 \\ 6 & 4 \end{pmatrix}\)

A. \(\begin{vmatrix} 2 & -\frac{3}{2} \\ -3 & -\frac{5}{2} \end{vmatrix}\)
B. \(\begin{vmatrix} 2 & -\frac{3}{2} \\ -3 & \frac{5}{2} \end{vmatrix}\)
C. \(\begin{vmatrix} 2 & \frac{3}{2} \\ -3 & \frac{5}{2} \end{vmatrix}\)
D. \(\begin{vmatrix} 2 & \frac{3}{2} \\ -3 & \frac{5}{2} \end{vmatrix}\)