1. System of Equations: Elimination
Ms. Stack

2. 10/19 Do Now
Turn your homework into the basket 

3. Elimination using Multiplication
Consider the system
6x + 11y = -5
6x + 9y = -3
*CFUs: What is the solution of this system of equations telling me?
Does anything cancel out right away? What could I change in order to cancel something out?

4. Elimination using Multiplication
Consider the system
6x + 11y = -5 +
6x + 9y = -3
12x + 20y = -8
When we add equations together,
nothing cancels out

5. Elimination using Multiplication
Consider the system
6x + 11y = -5
6x + 9y = -3

6. Elimination using Multiplication
Consider the system
-1 ( )
6x + 11y = -5
6x + 9y = -3

7. Elimination using Multiplication
Consider the system
x + 2y = 6
Multiply by -3 to eliminate the x term
3x + 3y = -6
CFUs: Does anything cancel out?
Can I graph these on my calculator and find the point of intersection? Why/why not?
Does it matter if x or y cancel out first?

8. Examples 1. 2.
x + 2y = 5
x + 2y = 4
2x + 6y = 12
x - 4y = 16

9. More complex Problems Consider the system 3x + 4y = -25 2x - 3y = 6
Multiply by 2
2x - 3y = 6
Multiply by -3

10. Examples… 2. 1.
2x + 3y = 1
4x + y = 9
5x + 7y = 3
3x + 2y = 8

11. Let’s Practice Word Problems
Today we will do #1 together and then you will do 2-4 on your own.
Please hold on to the sheet, we will finish them tomorrow 

12. Exit Ticket
Solve the system by using elimination: