Intermediate Algebra for College Students (7th Edition)

Published by Pearson
ISBN 10: 0-13417-894-7
ISBN 13: 978-0-13417-894-3

Chapter 3 - Section 3.4 - Matrix Solutions to Linear Systems - Exercise Set - Page 229: 7

Answer

The answer is $\left[\begin{array}{cc|c} 1 & -\frac{3}{2} & \frac{7}{2} \\ 0 &\frac{17}{2} &\frac{-17}{2} \\ \end{array}\right]$.

Work Step by Step

The given matrix is $\left[\begin{array}{cc|c} 1 & -\frac{3}{2} & \frac{7}{2} \\ 3 &4 &2 \\ \end{array}\right]$ Perform $ -3R_1+R_2 $. Multiply row 1 by $-3$ and add to the row 2 as shown below. $\left[\begin{array}{cc|c} 1 & -\frac{3}{2} & \frac{7}{2} \\ -3\cdot 1+3 &-3\cdot (-\frac{3}{2})+4 &-3\cdot (\frac{7}{2})+2 \\ \end{array}\right]$ Simplify. $\left[\begin{array}{cc|c} 1 & -\frac{3}{2} & \frac{7}{2} \\ -3+3 &\frac{9}{2}+4 &-\frac{21}{2}+2 \\ \end{array}\right]$ $\left[\begin{array}{cc|c} 1 & -\frac{3}{2} & \frac{7}{2} \\ 0 &\frac{9+8}{2} &\frac{-21+4}{2} \\ \end{array}\right]$ $\left[\begin{array}{cc|c} 1 & -\frac{3}{2} & \frac{7}{2} \\ 0 &\frac{17}{2} &\frac{-17}{2} \\ \end{array}\right]$.
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