# Thread: [SOLVED] determinant of a matrix.

1. ## [SOLVED] determinant of a matrix.

ok so i have this matrix

$\left[\begin{array}{cc}3&1\\-2&-4\end{array}\right]$

Need to find determinant.
$(3\cdot -4 )+(-2 \cdot 1) = -14$

Is this right , I'm not sure my lecture notes are correct.

or is it

$-(3\cdot -4 )+(-2 \cdot 1) = 10$

2. $(3\cdot -4 )-(-2 \cdot 1) = -10$