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 3.3 - Systems of Linear Equations in Three Variables - Exercise Set - Page 216: 19

Answer

Infinitely many solutions. Dependent equations.

Work Step by Step

The given equations are $\Rightarrow 5x-2y-5z=1$ ......(1) $\Rightarrow 10x-4y-10z=2$ ......(2) $\Rightarrow 15x-6y-15z=3$ ......(3) Multiply equation (1) by $-2$. $\Rightarrow -10x+4y+10z=-2$ ......(4) Now add equation (2) and (4). $\Rightarrow 10x-4y-10z-10x+4y+10z=2-2$ Add like terms. $\Rightarrow 0=0$ Multiply equation (1) by $-3$. $\Rightarrow -15x+6y+15z=-3$ ......(5) Now add equation (3) and (5). $\Rightarrow 15x-6y-15z-15x+6y+15z=3-3$ Add like terms. $\Rightarrow 0=0$ Hence, the given system of equations is a dependent system, meaning the equations are not truly unique. There is infinitely many solutions.
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