Chapter 1.1, Problem 1E

Use back substitution to solve each of the following systems of equations:

(a) $\begin{array}{l}{x}_1-3x_2=2\\ 2x_2=6\end{array}$

(b) $\begin{array}{l}{x}_1+x_2+x_3=8\\ 2x_2+x_3=5\end{array}$

(c) $\begin{array}{l}{x}_1+x_2+x_3+x_4=5\\ 3x_2+x_3-2x_4=1\end{array}$

(d) $\begin{array}{l}{x}_1+x_2+x_3+x_4+x_5=5\\ 2x_2+x_3-2x_4+x_5=1\\ 4x_3+x_4-2x_5=1\\ x_4-3x_5=0\\ 2x_5=2\end{array}$