Precalculus (10th Edition)

Published by Pearson
ISBN 10: 0-32197-907-9
ISBN 13: 978-0-32197-907-0

Chapter 11 - Systems of Equations and Inequalities - 11.3 Systems of Linear Equations: Determinants - 11.3 Assess Your Understanding - Page 742: 17

Answer

$(x,y) =(3,2)$

Work Step by Step

The given system of equations is $\left\{\begin{matrix} 5x& -&y&=&13\\ 2x& +&3y & =&12 \end{matrix}\right.$ Determinant $D$ consists of the $x$ and $y$ coefficients. $D=\begin{vmatrix} 5&-1 \\ 2& 3 \end{vmatrix}=(5)(3)-(2)(-1)=15+2=17$ For determinant $D_x$ replace the $x−$ coefficients with the constants. $D_x=\begin{vmatrix} 13& -1 \\ 12& 3 \end{vmatrix}=(13)(3)-(12)(-1)=39+12=51$ For determinant $D_y$ replace the $y−$ coefficients with the constants. $D_y=\begin{vmatrix} 5& 13 \\ 2& 12 \end{vmatrix}=(5)(12)-(13)(2)=60-26=34$ By using Cramer's rule we have. $x=\dfrac{D_x}{D}=\dfrac{51}{17}=3$ and $y=\dfrac{D_y}{D}=\dfrac{34}{17}=2$ Hence, the solution set is $(x,y) =(3,2)$.
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.