Solving Systems of Linear Equations by Elimination

4x +  8y = 20
-4x + 2y = -30
Which variable will be eliminated?

• The  x

• The  y

• The  z

• The unknown

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

 4x + 8y = 20
-4x + 2y = -30

• (-7,1)

• (2,-5)

• (-2,5)

• (7,-1)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

• (-2,2)

• (2,-2)

• (-2,-2)

• (-2, 1/2)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve by elimination:
3x+7y=23

-3x-7y=-17

• No solution

• ARN

• (-3,3)

• (3,3)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

-5x + 5y = -5

x - 5y = -7

• (3, 2)

• (-1, 3)

• Infinite solutions

• No solutions

Tags

CCSS.8.EE.C.8B

2x + 4y = 0

-5x - 4y = 18

• (6, -6)

• (-6, 3)

• Infinite solutions

• No solutions

Tags

CCSS.8.EE.C.8B

• -1

• 6

• 1

• -6

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve by elimination
4x-6y= -6
-2x-12y= -12

• (0,1) 

• (1,0)

• (1,1)

• (2,1)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve by elimination 
-6x+y= -2
-3x-6y= 12

• (2,0)

• no solution 

• (0,-2)

• infinite solutions 

Tags

CCSS.8.EE.C.8B

Solve the system by elimination.
4x + 12y = −1
−3x − 9y = 0 

• (10, 1) 

• (−10, −1) 

•  (10, −1) 

•  No solution 

Tags

CCSS.8.EE.C.8B