Thinking Mathematically (6th Edition)

Published by Pearson
ISBN 10: 0321867327
ISBN 13: 978-0-32186-732-2

Chapter 7 - Algebra: Graphs, Functions, and Linear Systems - 7.4 Linear Inequalities in Two Variables - Exercise Set 7.4 - Page 454: 25

Answer

See below:

Work Step by Step

Consider the provided inequalities: \[2x+y<3\]and\[x-y>2\] Replace each inequality symbol with an equal sign: \[2x+y=3\]and\[x-y=2\] Now, draw the graph of the equation\[2x+y=3\]. Put \[y=0\] for x-intercept and \[x=0\] for y-intercept in the equation\[2x+y=3\]. So, the x-intercept is \[\frac{3}{2}\] and y-intercept is 3. Therefore, the line is passing through \[\left( \frac{3}{2},0 \right)\]and\[\left( 0,3 \right)\]. Now, consider a test point\[\left( 0,0 \right)\], which lies in the half-plane. Substitute \[x=0\] and \[y=0\]in\[2x+y<3\]. \[\begin{align} & 0+0<3 \\ & 0<3 \end{align}\] Since \[\left( 0,0 \right)\]satisfies the above inequality \[2x+y<3\], the test point \[\left( 0,0 \right)\] is a part of the solution set. The solution should be the half plane, which is containing the point \[\left( 0,0 \right)\]. Since,\[2x+y<3\] is not contain an equal sign, the line should be dotted. Now, draw the graph of the equation\[x-y=2\]. Put \[y=0\] for x-intercept and \[x=0\] for y-intercept in the equation \[x-y=2\]. So, the x-intercept is 2 and y-intercept is \[-2\]. Therefore, the line is passing through \[\left( 2,0 \right)\]and \[\left( 0,-2 \right)\]. Now, consider a test point \[\left( 0,0 \right)\], which lies in the half-plane. Substitute \[x=0\] and \[y=0\]in \[x-y>2\]. \[\begin{align} & 0-0>2 \\ & 0>2 \end{align}\] \[\left( 0,0 \right)\]does notsatisfy the above inequality \[x-y>2\]. So, the test point \[\left( 0,0 \right)\] is not a part of the solution set. The solution should be the other half of the plane, which is not containing the point \[\left( 0,0 \right)\]. \[x-y>2\]is not contain an equal sign. So, the line should be dotted. Therefore, the graph of the linear inequality, \[2x+y<3\] and \[x-y>2\] is provided below:
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