1. Before: December 4, 2017 Solve each system by substitution. Steps:
Solve for one variable in one equation.
Substitute for that variable in the other equation.
Solve.
Replace to find the other variable.
Write your answer as an ordered pair.
Check your solution.

4. During: Solving Systems by Elimination
Learning Target: I can solve systems of linear equations in two variables by elimination using:
Addition
Subtraction
Multiplication (first)

5. Another method for solving systems of equations is elimination
Another method for solving systems of equations is elimination. Like substitution, the goal of elimination is to get one equation that has only one variable.

6. Solving Systems of Equations by Elimination
Step 1: Write the system so that like terms are aligned.
Step 2: Eliminate one of the variables and solve for the other variable.
Step 3: Substitute the value of the variable into one of the original equations and solve for the other variable.
Step 4: Write the answers from Steps 2 and 3 as an ordered pair, (x, y), and check.

7. “I Do” Elimination Using Addition
Solve by elimination.

8. “We Do” Elimination Using Addition
Solve by elimination.

9. “You Do” Elimination Using Addition
Solve by elimination.

10. “I Do” Elimination Using Subtraction
Solve by elimination.

11. “We Do” Elimination Using Subtraction
Solve by elimination.

12. “You Do” Elimination Using Subtraction
Solve by elimination.

13. In some cases, you will first need to multiply one or both of the equations by a number so that one variable has opposite coefficients.

14. “I Do” Elimination Using Multiplication First
Solve each system by elimination.

15. “We Do” Elimination Using Multiplication First
Solve each system by elimination.

16. “We Do” Elimination Using Multiplication First
Solve each system by elimination.

17. “You Do” Elimination Using Multiplication First
Solve each system by elimination.

18. Homework
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