For what value of $x$ is $\begin{vmatrix}1 & 2 & 3 \\ x & 1 & 0 \\ 2 & 1 & 1\end{vmatrix} = 0$?

Explanation

1. 01

   Expand along the first row: $1(1 - 0) - 2(x - 0) + 3(x - 2)$.

2. 02

   $= 1 - 2x + 3x - 6 = x - 5$, which is 0 when $x = 5$.