1. Warm Up 1. Graph y = 2x – 3 2. Graph y = ½ x + 2 3. Graph 6x + 3y = 9
Have students choose their own x values. Discuss why the graph is still the same even though they chose different values. Have them plot someone else’s points on their graph as well.

2. Warm Up Solve the following Equations 1. 5x + (3x – 5) = -25
Have students choose their own x values. Discuss why the graph is still the same even though they chose different values. Have them plot someone else’s points on their graph as well.

3. Solve Systems of Equations by Elimination

4. Steps for Elimination:
Arrange the equations with like terms in columns
Multiply, if necessary, to create opposite coefficients for one variable.
Add/Subtract the equations.
Substitute the value to solve for the other variable.
Write your answer as an ordered pair.
Check your answer.

5. EXAMPLE 1
(-1, 3)

6. EXAMPLE 2
4x + 3y = 16 2x – 3y = 8
(4, 0)

7. EXAMPLE 3
3x + 2y = 7 -3x + 4y = 5
(1, 2)

8. EXAMPLE 4
2x – 3y = -2 -4x + 5y = 2
(2, 2)

9. EXAMPLE 5
5x + 2y = 7 -4x + y = –16
(3, -4)

10. EXAMPLE 6
2x + 3y = 1 4x – 2y = 10
(2, -1)

11. Classwork (-1, 4) (-1, 2) (-2, 2) (1, 5) (5, -2) (4, -1) (-1/2, 4)
Add/Subtract
Use elimination to solve each system of equations.
1. -6x – 5y = m – 4n = a + b = 1
6x – 7y = m + 2n = a + b = 3
-3x – 4y = x – 3y = x – 2y = 6
-3x + y = x – 3y = x + y = 3
2a – 3b = x + 2y = x – y = 6
2a + 2b = x + 4y = x + 2y = 3
(-1, 4)
(-1, 2)
(-2, 2)
(1, 5)
(5, -2)
(4, -1)
(-1/2, 4)
(1/2, 2)
(1, -1)

12. Classwork (1, 1) (-3, 4) (-1, 2) (-1, 2) (4, -2) (-4, -2) (2, -1)
Multiply
Use elimination to solve each system of equations.
2x + 3y = m + 3n = a - b = 2
x + 2y = m + 2n = a + 2b = 3
4x + 5y = x – 3y = x – 4y = -4
6x - 7y = x – y = x + 3y = -10
4x – y = a – 3b = x + 2y = 5
5x + 2y = a + 2b = x - 4y = 10
(1, 1)
(-3, 4)
(-1, 2)
(-1, 2)
(4, -2)
(-4, -2)
(2, -1)
(-1/2, 2)
(2.5, 0)