Answer
$\sqrt{10}$
Work Step by Step
Here,
$\begin{align}
& {{a}_{1}}=2 \\
& {{a}_{2}}=-1 \\
& {{b}_{1}}=-5 \\
& {{b}_{2}}=-6
\end{align}$
Therefore,
$\begin{align}
& \mathbf{w}-\mathbf{u}=\left[ -1-2 \right]\mathbf{i}+\left[ -6-\left( -5 \right) \right]\mathbf{j} \\
& =-3\mathbf{i}-\mathbf{j}
\end{align}$
Therefore,
$\begin{align}
& \left\| \mathbf{w}-\mathbf{u} \right\|=\sqrt{{{\left( -3 \right)}^{2}}+{{\left( -1 \right)}^{2}}} \\
& =\sqrt{9+1} \\
& =\sqrt{10}
\end{align}$
