Solve Systems of Equations by Elimination

To solve a system with elimination, we look for ​ ​ (a)   ​ . Then, we​ (b)   ​ and solve. Once we know that variable, we ​ (c)   .

• a match for one of the variables

• subtract e-very-thing

• plug in our answer to find the other

• are done

• plug in the "chunk" to the other equation

• a variable equal to a "chunk" of information

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

• (-4, -2)

• (2, 5)

• (10, 2)

• (-8, -1)

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

Solve for x and solve for y
3x  - 3y = 33
6x - 3y = 57

• (8,-3)

• (-3,8)

• (10,1)

• (10,-1)

Tags

CCSS.HSA.REI.C.9

• (3, 3)

• (1, 5)

• (1, 3)

• (7, -1)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve the system of Equation (x,y)
3x + 2y = –13
3x + 4y = 1 

• (-9,7)

• (7,-9)

• (4,-7)

• (-7,-4)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve using elimination.
7x + 2y = 24
8x + 2y = 30

• (6,-9)

• (-9,6)

• No solution

• Infinite number of solutions

Tags

CCSS.8.EE.C.8B

Solve by elimination:
4x + 4y = 4
3x + 4y =10

• (7,-6)

• (-6,7)

• (6,7)

• (7,6)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve the system of equations
  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