Question

Evaluate the determinant $\left|\begin{array}{ccc}2& 3& -5\\ 7& 1& -2\\ -3& 4& 1\end{array}\right|$

Answer 1

$\left|\begin{array}{ccc}2& 3& -5\\ 7& 1& -2\\ -3& 4& 1\end{array}\right|$

Expanding the determinant, we get

$=2(1+8)-3(7-6)-5(28+3)$

$=18-3-155$

$=-140$