Question

Find the value of determinant :

\( \begin{vmatrix} 1& 3& 9 \\[0.3em] 3 & 9 &1 \\[0.3em] 9 & 1 &3 \end{vmatrix}\)

Answer 1

 \( \begin{vmatrix} 1& 3& 9 \\[0.3em] 3 & 9 &1 \\[0.3em] 9 & 1 &3 \end{vmatrix}\)

= 1(27 – 1) – 3(9 – 9) + 9(3 – 81)

= 26 – 0 – 702

= -676.