Matrices and Determinants - Jamb Mathematics Past Questions and Answers

Question 26:

• JAMB 2006

If x = \(\begin{pmatrix} 1 & 0 & 1 \\ 2 & -1 & 0 \\ -1 & 0 & 1\end{pmatrix}\) and y = \(\begin{pmatrix} -1 & 1 & 2 \\ 0 & -1 & -1 \\ 2 & 0 & 1\end{pmatrix}\)
find 2x - y

A. \(\begin{pmatrix} 3 & -1 & 0 \\ 4 & -3 & -1 \\ -4 & 1 & 1\end{pmatrix}\)
B. \(\begin{pmatrix} 3 & -1 & 0 \\ 4 & -1 & 1 \\ -4 & 1 & 1\end{pmatrix}\)
C. \(\begin{pmatrix} 3 & -1 & 0 \\ 4 & -3 & 1 \\ -4 & 1 & 1\end{pmatrix}\)
D. \(\begin{pmatrix} 3 & -1 & 0 \\ 4 & 1 & 1 \\ -4 & -1 & 1\end{pmatrix}\)

Question 27:

• JAMB 2008

Find the values of x and y respectively if
\(\begin{pmatrix} 1 & 0 \\ -1 & -1\\ 2 & 2 \end{pmatrix}\) + \(\begin{pmatrix} x & 1 \\ -1 & 0\\ y & -2 \end{pmatrix}\) = \(\begin{pmatrix} -2 & 1 \\ -2 & -1\\ -3 & 0 \end{pmatrix}\)

A. -3, -2
B. -5, -3
C. -2, -5
D. -3, -5

Question 28:

• JAMB 2008

\(\begin{pmatrix} -2 & 1 \\ 2 & 3 \end{pmatrix}\) + \(\begin{pmatrix}p & q \\ r & s\end{pmatrix}\) = \(\begin{pmatrix} 1 & 0 \\0 & 1 \end{pmatrix}\). What is the value of r?

A. -\(\frac{1}{8}\)
B. \(\frac{3}{8}\)
C. \(\frac{5}{8}\)
D. \(\frac{1}{4}\)

Question 29:

• JAMB 2009

If Q is\( \left[ \begin{array}{cc}
9 & -2 \\
-7 & 4 \\
\end{array} \right]\) , then |Q| is

A. -50
B. -22
C. 22
D. 50

Question 30:

• JAMB 2009

If P \(=\left[\begin{array}{cc}x+3 & x+2\\
x+1 & x-1\end{array}\right]\) evaluate x if |P| = -10

A. -5
B. -2
C. 2
D. 5