1. Bellringer on Goformative!
Bellringer on Goformative!
Objective: I can solve
a system of linear
equations algebraically,
using substitution or elimination.

2. I CAN solve a system of equations algebraically
Learning Target
I CAN solve a system of equations algebraically
by ELIMINATION.

3. Agenda: Notes what if there is NO SUB? Examples of Elimination
(my fav!)
Solving Systems Scavenger Hunt
EXIT TICKET

4. One equation to get y= something
𝑥+𝑦=4
−𝑥+𝑦=2
No sub!
Can you rearrange
One equation to get y= something
Or x=something?

5. 𝑥+𝑦=4
Could we move x to other side?
−𝑥+𝑦=2

6. 𝑥+𝑦=4
−𝑥+𝑦=2

7. What if I told you, when both eqns
𝑥+𝑦=4
−𝑥+𝑦=2
What if I told you, when both eqns
Are in standard form, there could be
An easier way?

8. 𝑥+𝑦=4 −𝑥+𝑦=2 ELIMINATION 2𝑦=6 2 y = 3
Add both eqns together and the x’s cancel or eliminate. Line up like terms, x, y, = constant. Must be in standard form.

9. 𝑥+𝑦=4
−𝑥+𝑦=2
2𝑦=6 2
y = 3
𝑥+𝑦=4
𝑥+3=4
x = 1

12. Ex 1: Elimination Method
x – y = 11
2x + y = 19
What would eliminate?

13. Ex 2: Elimination Method
4x + 8y = 20
-4x + 2y = -30

14. Ex 3: Elimination Method
7x + 2y = 24
8x + 2y = 30
Nothing would eliminate, but if 2y was negative it would. Since we can add, sub, mult divide by anything, we could multiply second eqn by -1 and them use elimination method. Do not discuss with 2nd block.

15. Ex 4: Elimination Method
5x + y = 9
10x - 7y = -18
Would either multiply 1st equan by -2 or +7

16. Substitution or elimination?
Which method
Would be best-
Substitution or elimination?
Don’t solve just pick method

17. Solving Systems by Substitution or Elimination Scavenger Hunt
You pick the method!
Find the solution.
Everyone start at a different place,
Write Letter, system, solve then look
For sol around room, repeat at next station.
You have 30 mins.
Would either multiply 1st equan by -2 or +7

18. If you get it incorrect-look carefully at work
Check solutions
In GOFO!
If you get it incorrect-look carefully at work
And try again.
Would either multiply 1st equan by -2 or +7

19. Solve the system by elimination:
Exit Ticket
Solve the system by elimination:
A no solution
B y =0
C x = 4.5
D x=-12