Unit 1.3

USE YOUR CALCULATOR!!!

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Unit 1 – Algebra: Linear Systems, Matrices, & Vertex-Edge Graphs 1.3 – Solve Linear Systems

Algebraically Georgia Performance Standard:

MM3A5c – Represent and solve realistic problems using systems of linear equations.

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Vocabulary

Substitution method Elimination method

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Substitution Method

Step 1: Solve one of the equations for one of it’s

variables (x or y…Your choice!) Step2:

Plug in what you found (or substitute) into the other equation

Step 3: Substitute what you got from Step 2 into

either of the original equations and solve for the other variable.

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Ex. 1 Solve the system using the substitution

method.

6x + 3y = 12 Equation 13x + y = 5 Equation 2

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Try These…

Page 13: 1-3 Use the Substitution Method

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Elimination Method

Step 1: Multiply one or both of the equations by a

constant to get coefficients that differ only in sign for one of the variables

Step2: Add revised equations from Step 1 and

solve for remaining variable Step 3:

Substitute the value from Step 2 into either of the original equations and solve for the other variable

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Ex. 2 Solve the system using the elimination

method.

5x + 7y = 2450 Equation 18x + 13y = 4325 Equation 2

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Use the Elimination Method…1.) 2.) 2x + 4y = -4 2x + y = -3x – 2y = 10 -6x – 4y = 0

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Linear Systems with many or no solutions9x – 3y = 63x – y = 2

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Linear Systems with many or no solutionsx – 2y = 54x – 8y = 3

Homework

Page 15: 1-3 (Use the Substitution Method) 7-9 (Use the Elimination Method) 15, 19, & 21 (Use either the Substitution

or Elimination Method) Make sure to show your work and circle

your answers!

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