6.3 – solving systems of linear equations by elimination. definitions of the day (dods) review of...

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6.3 – Solving Systems of Linear Equations by Elimination. Definitions of the Day (DODs) Review of Ch 6 Systems of Equations So Far… 6.1 Graphing 6.2 Substitution Method 6.3 Elimination Method

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Page 1: 6.3 – Solving Systems of Linear Equations by Elimination. Definitions of the Day (DODs) Review of Ch 6 Systems of Equations So Far… 6.1 Graphing 6.2 Substitution

6.3 – Solving Systems of Linear Equations by Elimination.

Definitions of the Day (DODs)

Review of Ch 6 Systems of Equations So Far…

6.1 Graphing

6.2 Substitution Method

6.3 Elimination Method

Review of Ch 6 Systems of Equations So Far…

6.1 Graphing

6.2 Substitution Method

6.3 Elimination Method

Page 2: 6.3 – Solving Systems of Linear Equations by Elimination. Definitions of the Day (DODs) Review of Ch 6 Systems of Equations So Far… 6.1 Graphing 6.2 Substitution

Definition: Elimination Method –Eliminate one of the variables by adding (or subtracting) the equations of the system.  

Definition: Elimination Method –Eliminate one of the variables by adding (or subtracting) the equations of the system.  

Let us Explore…Let us Explore…

+ =x y 10x - y = 36

Top Equation

Bottom Equation( )+ 2x = 46

+

Y has been ELIMINATED

x =23, y =-13 Solve for x, Substitute for y

Page 3: 6.3 – Solving Systems of Linear Equations by Elimination. Definitions of the Day (DODs) Review of Ch 6 Systems of Equations So Far… 6.1 Graphing 6.2 Substitution

Steps to the Elimination Method!!Steps to the Elimination Method!!

1. Pick One Variable to Eliminate! (Either x or y.)

2. Eliminate the Variable by adding or subtracting the equations together.

3. Substitute & Solve for the last Variable.

Page 4: 6.3 – Solving Systems of Linear Equations by Elimination. Definitions of the Day (DODs) Review of Ch 6 Systems of Equations So Far… 6.1 Graphing 6.2 Substitution

Example #1Example #1

5x - 6y = -323x + 6y = 48

Page 5: 6.3 – Solving Systems of Linear Equations by Elimination. Definitions of the Day (DODs) Review of Ch 6 Systems of Equations So Far… 6.1 Graphing 6.2 Substitution

X+Y=6

Example #2Example #2

X+3Y=10

Page 6: 6.3 – Solving Systems of Linear Equations by Elimination. Definitions of the Day (DODs) Review of Ch 6 Systems of Equations So Far… 6.1 Graphing 6.2 Substitution

WARNING!WARNING!

• WE MAY NEED TO MANIPULATE ONE OF

THE EQUATIONS BEFORE SOLVING FOR

A VARIABLE!

Page 7: 6.3 – Solving Systems of Linear Equations by Elimination. Definitions of the Day (DODs) Review of Ch 6 Systems of Equations So Far… 6.1 Graphing 6.2 Substitution

3x + 4y = -105x - 2y = 18

Example #3(One Solution)Example #3(One Solution)

Page 8: 6.3 – Solving Systems of Linear Equations by Elimination. Definitions of the Day (DODs) Review of Ch 6 Systems of Equations So Far… 6.1 Graphing 6.2 Substitution

6x - 9y = 9

Example #4(No Solution)Example #4(No Solution)

2x - 3y = 6

Page 9: 6.3 – Solving Systems of Linear Equations by Elimination. Definitions of the Day (DODs) Review of Ch 6 Systems of Equations So Far… 6.1 Graphing 6.2 Substitution

x + 4y = 1

Example #5(Infinitely Many Solutions)

Example #5(Infinitely Many Solutions)

3x + 12y = 3

Page 10: 6.3 – Solving Systems of Linear Equations by Elimination. Definitions of the Day (DODs) Review of Ch 6 Systems of Equations So Far… 6.1 Graphing 6.2 Substitution

Solve by ELIMINATION

1. X+ y = 12 2. 4x - 2y = 6

x - y = 2 -2x + y = -3

Solve by ELIMINATION

1. X+ y = 12 2. 4x - 2y = 6

x - y = 2 -2x + y = -3

Your Turn!!Your Turn!!

Page 11: 6.3 – Solving Systems of Linear Equations by Elimination. Definitions of the Day (DODs) Review of Ch 6 Systems of Equations So Far… 6.1 Graphing 6.2 Substitution

Sentence FramesSentence Frames

1. The Goal of Solving a System of Equations by Elimination is __________________________________________________________________________________________________

2. The Three methods for solving a System of Equations are

1. _______________

2. _______________

3. _______________

1. The Goal of Solving a System of Equations by Elimination is __________________________________________________________________________________________________

2. The Three methods for solving a System of Equations are

1. _______________

2. _______________

3. _______________