Evaluate 2&5 -1&-1 - Vidyadip

MCQ

Evaluate $\begin{bmatrix}2&5\\-1&-1\end{bmatrix}$

✓
$3$
B
$-7$
C
$5$
D
$-2$

✓

Answer

Correct option: A.

$3$

Expanding along $\text{R}_1,$ we get
$\triangle=2(-1)-5(-1)$
$=-2+5$
$=3$

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