Systems of Equations (Elimination by Addition)

Solve the system by using elimination.

• (8, -1)

• (-1, 8)

• (-1, 3)

• (3, -1)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

What would be the first step in finding the solution with elimination?

4x + 3y = 1

x - 3y = -11

• cross out the 3y and -3y

• cross out the 4x and x

• change all the signs of the second equation

• add 1 and -11

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

what is the resulting combined equation to the following system:

• 5x = -3

• 10y = -3

• 10x = -3

• 10x = -25

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

what is the variable that willl be "eliminated"?

5x - 4y = 11

5x + 4y = -14

• x variable

• y variables

• both variables

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

what would the top equation become when you multiply everything by -1?

• 2x - 6y = 20

• -2x - 6y = -20

• -2x + 6y = 20

• -2x + 6y = -20

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve using elimination. 
−4x − 4y = 0
4x + 4y = 0 

• (−6, −4) 

• Infinite number of solutions  

• (−6, 10) 

• (6, 4) 

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve the system by elimination.  

−8x − 10y = 20
−8x − 6y = −4 

• Infinite number of solutions  

• (6, 5) 

• (−6, −5) 

• (5, −6) 

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

-6x+5y=1
           6x+4y=-10

• (1,1)

• (-1,-1)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

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

• (-7,0)

• (6,0)

• (-6,0)

• (7,0)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Which variable is the easiest to eliminate in this system?

• x

• y

• both

• neither

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6