1. Mr. Hartzer, Hamtramck High School 2017-18
Algebra II
Mr. Hartzer, Hamtramck High School

2. DO NOW

3. DO NOW (Honors)

4. This Week’s Objective
Students will: solve linear equations and inequalities using graphs and algebraic methods.

5. Today’s Objective
Students will: use substitution and elimination to solve linear systems exactly.
CCSS: A-REI.C.6; A-REI.C.5; A-CED.A.2

6. Today’s Agenda
Do Now
Review homework
Notes: Algebraic Techniques
Practice

7. Solving by Elimination
To solve by elimination:
(1) Multiply one or both equations to create matching coefficients.
(2) Take the difference of the equations to eliminate one variable.
(3) Solve for the value of the other variable.
(4) Use this value in either equation to solve for the value of the first variable.

8. Solving by Elimination
Example:
3𝑥+4𝑦=12
2𝑥+𝑦=10
(1) Multiply one or both equations to create matching coefficients.
4 2𝑥+𝑦= ⇒ 𝑥+4𝑦=40

9. Solving by Elimination
Example:
(2) Take the difference of the equations to eliminate one variable.
8𝑥+4𝑦=40
3𝑥+4𝑦=12
5𝑥=28

10. Solving by Elimination
Example:
(3) Solve for the value of the variable.
5𝑥=28
𝑥=5.6

11. Solving by Elimination
Example:
(4) Use this value in either equation to solve for the value of the first variable.
2𝑥+𝑦=10
𝑦=10
𝑦=−1.2

12. Solving by Elimination
Example:
3𝑥+4𝑦=12
2𝑥+𝑦=10
Solution:
Both lines pass through (5.6, −1.2)

13. Solving by Elimination
Solution:

14. Solving by Elimination
Solution:

15. Solving by Elimination
Solution:

16. Classwork
Complete the worksheet. Work with your neighbor.