Evaluate $2 \times 2$ determinant. $$\left| \begin{array} { r r }
- 2 & - 5 \
- 1 & - 9
\end{array} \right|$$
A) 13
B) 20
C) -5

Name: Evaluate $2 \times 2$ determinant. \[\left| \begin{array} { r r } - 2 & - 5 \\ - 1 & - 9 \end{array} \right|\] A) 13 B) 20 C) -5
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Question

Evaluate $2 \times 2$ determinant. $$\left| \begin{array} { r r } 
- 2 & - 5 \
- 1 & - 9
\end{array} \right|$$
A) 13
B) 20
C) -5

Quizplus · Accepted Answer

The determinant of a $2 \times 2$ matrix $\left| \begin{array} { r r } a & b \ c & d \end{array} \right|$ is calculated as $ad - bc$. For this matrix, it is $(-2) \times (-9) - (-5) \times (-1) = 18 - 5 = 13$.

Evaluate 2×22 \times 22×2 Determinant ∣−2−5−1−9∣\left| \begin{array} { r r } - 2 & - 5 \\- 1 & - 9\end{array} \right|​−2−1​−5−9​​

Evaluate $2 \times 2$ Determinant $\left| \begin{array} { r r } - 2 & - 5 \\- 1 & - 9\end{array} \right|$