Precalculus (6th Edition) Blitzer

Published by Pearson
ISBN 10: 0-13446-914-3
ISBN 13: 978-0-13446-914-0

Chapter 8 - Mid-Chapter Check Point - Page 920: 5

Answer

The system of equations has no solution.

Work Step by Step

Consider the following system of equations: $\begin{align} & 2x-2y+2z=5 \\ & x-y+z=2 \\ & 2x+y-z=1 \end{align}$ The matrix corresponding to the system of equations is as follows: $\left[ \begin{matrix} 2 & -2 & 2 & 5 \\ 1 & -1 & 1 & 2 \\ 2 & 1 & -1 & 1 \\ \end{matrix} \right]$ Using the elementary row transformation we will obtain the echelon form of the matrix. ${{R}_{1}}\to \frac{1}{2}{{R}_{1}}$ gives, $\left[ \begin{matrix} 1 & -1 & 1 & \frac{5}{2} \\ 1 & -1 & 1 & 2 \\ 2 & 1 & -1 & 1 \\ \end{matrix} \right]$ ${{R}_{2}}\to {{R}_{2}}+\left( -1 \right){{R}_{1}},\text{ }{{\text{R}}_{3}}\to {{R}_{3}}+\left( -2 \right){{R}_{1}}$ gives, $\left[ \begin{matrix} 1 & -1 & 1 & \frac{5}{2} \\ 0 & 0 & 0 & -\frac{1}{2} \\ 0 & 3 & -3 & -4 \\ \end{matrix} \right]$ ${{R}_{2}}\leftrightarrow {{R}_{3}}$ gives, $\left[ \begin{matrix} 1 & -1 & 1 & \frac{5}{2} \\ 0 & 3 & -3 & -4 \\ 0 & 0 & 0 & -\frac{1}{2} \\ \end{matrix} \right]$ ${{R}_{3}}\to {{R}_{3}}+1{{R}_{2}}$ gives, $\left[ \begin{matrix} 1 & 2 & \frac{5}{2} & 1 \\ 0 & -1 & -\frac{1}{2} & 0 \\ 0 & 0 & 0 & 1 \\ \end{matrix} \right]$ Since, in the last row $0\ne 1$, this implies that the system is inconsistent, and has no solution.
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.