Question

If \[\begin{bmatrix}x & 1\end{bmatrix}\begin{bmatrix}1 & 0 \\ - 2 & 0\end{bmatrix} = O\]  , find x.

Answer 1

\[\begin{bmatrix}x & 1\end{bmatrix}\begin{bmatrix}1 & 0 \\ - 2 & 0\end{bmatrix} = O\]

\[ \Rightarrow \begin{bmatrix}x - 2 & 0 + 0\end{bmatrix} = \begin{bmatrix}0 & 0\end{bmatrix}\]

\[ \Rightarrow \begin{bmatrix}x - 2 & 0\end{bmatrix} = \begin{bmatrix}0 & 0\end{bmatrix}\]

\[ \Rightarrow x - 2 = 0\]

\[ \Rightarrow x = 2\]

∴ x = 2.