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 - 7.3 Systems of Linear Equations in Two Variables - Exercise Set 7.3 - Page 446: 69

Answer

A system of linear equations can be solved using the addition method. This involves isolating a variable and solving an equation consisting of only one variable.

Work Step by Step

A system of linear equations can be solved using the addition method. This involves isolating a variable and solving an equation consisting of only one variable. This is done by using addition of two equations to eliminate a variable. For example, consider the system \[\begin{align} & 3x+5y=-2 \\ & 2x+3y=0 \\ \end{align}\] Now, \[x\] coefficient of both the equations is made same by multiplying the first equation with \[2\] and the second equation by \[-3\]. The equations are then added as follows: \[\begin{align} & \text{ }6x+10y=-4 \\ & \underline{-6x-9y=0\text{ }} \\ & \text{ }y=-4 \\ \end{align}\] Substitute this value in any of the equation to find the value of \[x\] \[\begin{align} & 2x+3(-4)=0 \\ & x=6 \end{align}\] Thus, the solution of the system of equations is ordered pair \[\left( 6,-4 \right)\].
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