College Algebra (6th Edition)

Published by Pearson
ISBN 10: 0-32178-228-3
ISBN 13: 978-0-32178-228-1

Chapter 5 - Systems of Equations and Inequalities - Exercise Set 5.1 - Page 531: 99

Answer

$(\displaystyle \frac{c_{1}b_{2}-c_{2}b_{1}}{a_{1}b_{2}-a_{2}b_{1}},\ \ \frac{c_{1}a_{2}-c_{2}a_{1}}{b_{1}a_{2}-b_{2}a_{1}}),\quad a_{1}b_{2}\neq a_{2}b_{1}$

Work Step by Step

Eliminating x, multiply the first equation with $a_{2}$ and the second with $-a_{1}$ $\left\{\begin{array}{l} a_{1}a_{2}x+b_{1}a_{2}y=c_{1}a_{2}\\ -a_{1}a_{2}x-b_{2}a_{1}y=-c_{2}a_{1} \end{array}\right.$ add the equations $(b_{1}a_{2}-b_{2}a_{1})y=c_{1}a_{2}-c_{2}a_{1}$ $y=\displaystyle \frac{c_{1}a_{2}-c_{2}a_{1}}{b_{1}a_{2}-b_{2}a_{1}},\quad a_{1}b_{2}\neq a_{2}b_{1}$ Similarly, eliminating y, multiply the first equation with $b_{2}$ and the second with $-b_{1}$ $\left\{\begin{array}{l} a_{1}b_{2}x+b_{1}b_{2}y=c_{1}b_{2}\\ -a_{2}b_{1}x-b_{2}b_{1}y=-c_{2}b_{1} \end{array}\right.$ add the equations $(a_{1}b_{2}-a_{2}b_{1})x=c_{1}b_{2}-c_{2}b_{1}$ $x=\displaystyle \frac{c_{1}b_{2}-c_{2}b_{1}}{a_{1}b_{2}-a_{2}b_{1}},\quad a_{1}b_{2}\neq a_{2}b_{1}$
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