1. Is the matrix below in reduced row-echelon form? Why or why not? \begin{equation*} \begin{bmatrix} 1 & 5 & 0 & 6 & 8\\ 0 & 0 & 1 & 2 & 0\\ 0 & 0 & 0 & 0 & 1 \end{bmatrix} \end{equation*}
  2. Use row operations to convert the matrix below to reduced row-echelon form and report the final matrix. \begin{equation*} \begin{bmatrix} 2 & 1 & 8\\ -1 & 1 & -1\\ -2 & 5 & 4 \end{bmatrix} \end{equation*}
  3. Find all the solutions to the system below by using an augmented matrix and row operations. Report your final matrix in reduced row-echelon form and the set of solutions. \begin{align*} 2x_1 + 3x_2 - x_3&= 0\\ x_1 + 2x_2 + x_3&= 3\\ x_1 + 3x_2 + 3x_3&= 7 \end{align*}