Show that $\left\{\mathbf{u}_{1}, \mathbf{u}_{2}\right\}$ or $\left\{\mathbf{u}_{1}, \mathbf{u}_{2}, \mathbf{u}_{3}\right\}$ is an orthogonal basis for $\mathbb{R}^{2}$ or $\mathbb{R}^{3},$ respectively. Then express $\mathbf{x}$ as a linear combination of the $\mathbf{u}^{\prime}$s.
$\mathbf{u}_{1}=\left[\begin{array}{l}{1} \\ {0} \\ {1}\end{array}\right], \mathbf{u}_{2}=\left[\begin{array}{r}{-1} \\ {4} \\ {1}\end{array}\right], \mathbf{u}_{3}=\left[\begin{array}{r}{2} \\ {1} \\ {-2}\end{array}\right],$ and $\mathbf{x}=\left[\begin{array}{r}{8} \\ {-4} \\ {-3}\end{array}\right]$