Solving Systems by Elimination

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

• (-1, -1)

• (2,-1)

• (1,1)

• (1,-1)

• (-1,2)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

What is the resulting combined equation for the system below?

• -18x = 18

• y = 18

• 2y= 18

• 18x + 2y = 18

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Work Must be shown:

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

7x - y = 10

-7x + y = -14

• No Solution

• (4, 1)

• Infinitely Many Solutions

• (2, -4)

Answer explanation

7x - y = 10

-7x + y = -14

All of the like terms have opposite coefficients, so both variables will be eliminated when we add the equations together. We cannot eliminate one without the other.

We are left with:

0=-4

This is a contradiction (false), so there is NO SOLUTION.

Tags

CCSS.8.EE.C.8B

Work Must be shown:

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

• (-2, -3) 
• (-2, 3)
• (2, -3)
• (2, 3) 

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

-3x+3y = 18
5x-3y = -26
answers in (x,y)

• (4,2)

• (-4,-2)

• (-4,2)

• (4,-2)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

What is the solution?

• (1, -2)

• (-2, 1)

• (-4, 1)

• (2, 1)

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)

• (0, 2)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6