Find the determinant of the matrix. $$\left[ \begin{array} { c c }
7 & 1 \
- 1 & 2
\end{array} \right]$$
A)15
B)13
C) $- 13$
D) $- \frac { 1 } { 13 }$
E) $- 15$

Question

Find the determinant of the matrix.​ $$\left[ \begin{array} { c c } 
7 & 1 \
- 1 & 2
\end{array} \right]$$ ​
A)15
B)13
C) $- 13$
D) $- \frac { 1 } { 13 }$
E) $- 15$

Quizplus · Accepted Answer

The determinant of a 2x2 matrix $\left[ \begin{array} { c c } a & b \ c & d \end{array} \right]$ is calculated as $ad - bc$. For this matrix, it is $7 \times 2 - 1 \times (-1) = 14 + 1 = 15$.

Find the Determinant of the Matrix [71−12]\left[ \begin{array} { c c } 7 & 1 \\- 1 & 2\end{array} \right][7−1​12​]

Find the Determinant of the Matrix $\left[ \begin{array} { c c } 7 & 1 \\- 1 & 2\end{array} \right]$