Elementary Technical Mathematics

Published by Brooks Cole
ISBN 10: 1285199197
ISBN 13: 978-1-28519-919-1

Chapter 9 - Section 9.2 - Solving Pairs of Linear Equations by Addition - Exercises - Page 332: 26


No solution; parallel lines.

Work Step by Step

We use the addition method: We add the 2 equations: $4x+7y=9$ $12x+21y=12$ Multiply both sides of the first equation by $-3$ to cancel $x$. $-12x-21y=-27$ $\underline{+12x+21y=+12}$ $0=-15$ This is a false statement. Thus, the two equations are parallel. No solution.
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