Question
Find the values of the determinants : $\left|\begin{array}{cc}2 & -4 \\ 7 & -15\end{array}\right|$
✓
Answer
$\left|\begin{array}{lr}
2 & -4 \\
7 & -15
\end{array}\right| $
$=2(-15)-(-4)(7)$
$=-30+28$
$=-2 $
2 & -4 \\
7 & -15
\end{array}\right| $
$=2(-15)-(-4)(7)$
$=-30+28$
$=-2 $
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