Evaluate the determinant. $\left| \begin{array} { c c }
- 4 & - 9 \
- 7 & 3
\end{array} \right|$
A) $75$
B) $- 75$
C) $- 12$
D) $- 63$
E) $- 72$

Question

Evaluate the determinant. $\left| \begin{array} { c c } 
- 4 & - 9 \
- 7 & 3
\end{array} \right|$
A) $75$
B) $- 75$
C) $- 12$
D) $- 63$
E) $- 72$

Quizplus · Accepted Answer

The determinant can be found by cross multiplying the numbers in the diagonal and then subtracting the product of the other two numbers. In this case, we have:
$$\begin{aligned} \left| \begin{array} { c c } 
- 4 & - 9 \
- 7 & 3
\end{array} ight| &= (-4 \cdot 3) - (-9 \cdot -7) \
&= -12 - 63 \
&= -75
\end{aligned}$$
Therefore, the correct answer is B) $-75$.

Evaluate the Determinant ∣−4−9−73∣\left| \begin{array} { c c } - 4 & - 9 \\- 7 & 3\end{array} \right|​−4−7​−93​​

Evaluate the Determinant $\left| \begin{array} { c c } - 4 & - 9 \\- 7 & 3\end{array} \right|$