System of Equations by Elimination

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

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

Solve by elimination:

-9x-4y=-20

5x+4y=4

• (-4,4)

• (4,4)

• (4,-4)

• (-4,-4)

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

-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 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 variable that will 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 do you need to multiply the top equation by to make a zero pair:

5x - 2y = 11

-10x + 3y = -4

• 5

• -1

• 2

• -2

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve by elimination:

7x+y=-9

-3x-y=5

• No solution

• (1,8)

• (-1,-3)

• (-1,-2)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve by elimination

-6x + 5y = 1

6x + 4y = -10

• (-1,7/5)

• (0,-1)

• (1,1)

• (-1,-1)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6