lesson 7 - choosing the best method to solve.notebook · lesson 7 choosing the best method to...
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Lesson 7 Choosing the Best Method to Solve.notebook
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April 18, 2019
Lesson # 7 Choosing the Best Method to Solve
By the end of this lesson I will be able to choose the best method to solve a linear system.
Learning Goal
Which Method Would you Choose?
Graphing,
Substitution
OR
Elimination?
Lesson 7 Choosing the Best Method to Solve.notebook
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April 18, 2019
What we've used so far to SOLVE a system:
0) Graphing: okay if an exact point is obtained.
1) Both equations in y = mx + b form: Use substitution by equating the two sides directly.
Ex: y= 2x 5 and y = 4x + 2
2) In at least one equation, a variable is by itself: rearrange (if needed) to get that variable by itself and substitution is used.
Ex: 2x 5y + 4 = 0 and 2x + y 5 = 0
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3) If the numerical coefficients of the same variable are the same (both 3x or both 2y) then use elimination. (Both the same sign you subtract them and if different signs you add).
Ex: 2x 4y = 7 and 3x + 4y = 2
System A
What method would you use and why?
Lesson 7 Choosing the Best Method to Solve.notebook
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April 18, 2019
What method would you use and why?
What method would you use and why?
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For System A, determine if you can solve the system using each of the three methods you have learned, and if you can, then solve using that method.
1. Graphing
Justification:
System A
2. Substitution Justification:
System A
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3. Elimination Justification:
System A
For System B, determine if you can solve the system using each of the three methods you have learned, and if you can, then solve.
1. Graphing
Justification:
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2. Substitution Justification:
3. Elimination Justification:
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For System C, determine if you can solve the system using each of the three methods you have learned, and if you can, then solve.
1. Graphing
Justification: x
y
5
5
5
5
10
10
10
10
2. Substitution Justification:
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3. Elimination Justification:
Solving Word Problems Practice (use Substitution OR Elimination to
solve each question)
1. p.209211 #4, 5, 6, 8 (next slide has #4 and 5)2. p.216217 #5, 6
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Lesson 7 Choosing the Best Method to Solve.notebook
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April 18, 2019