A System by Elimination

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

• The  x
• The  y
• The  z
• The unknown

Solve by elimination:
4x+9y=28
-4x-y=-28

• (-7,0)
• (6,0)
• (-6,0)
• (7,0)

Solve by elimination:
3x+7y=23

-3x-7y=-17

• No solution
• ARN
• (-3,3)
• (3,3)

Solve by elimination:
4x+4y=4

3x+4y=10

• (7,-6)
• (-6,7)
• (6,7)
• (7,6)

Solve by elimination:
-x+2y=17

2x+2y=-10

• ARN
• (-9,4)
• (-9,-4)
• (9,-4)

Solve by elimination:

7x-9y=29

7x+2y=-15

• (-4,-1)

• (-1,-4)

• (-1,4)

• (-1,6)

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

• (0,1) 
• (1,0)
• (1,1)
• (2,1)

Solve by elimination 
2x+9y= -7 
6x-3y= 9 

• (-1, -1) 
• (2,-1)
• (1,1)
• (1,-1)

Solve by elimination:
7x + y = -9
-3x - y = 5

• No solution
• (1,8)
• (-2,-3)
• (-1,-2)

Solve by elimination:
x + 9y = 8
-6x - 9y = -3

• (1,-1)
• (1,1)
• (-1,1)
• (-1,-1)