Elimination Opposite Coefficients

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

Solve using Elimination Method:

4x + 9y = 28

-4x - y = -28

• (-7,0)

• (6,0)

• (-6,0)

• (7,0)

• (6,7)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve using Elimination Method:

x - y = 11

2x + y = 19

• (10,-1)

• (-1,10)

• (3,-4)

• (6,7)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

-5y+8x=-18

57y+2x=58

• (2,11)

• (7,6)

• (3,6)

• (4,10)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve using elimination method.

x-y=11

2x+y=19

• (10,-1)

• (-1,10)

• (3,-4)

• (6,7)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Let's multiply the top equation by -2. What would be our new equation?

2x + 3y = 12

4x - 7y = - 54

• 4x - 6y = -24

• -4x - 6y = 12

• -4x - 6y = 24

• -4x - 6y = -24

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

-4x - 6y = -24

4x - 7y = - 54

Let's combine (add) these 2 equations to ELIMINATE the x variable. What would our combined equations be?

• -1y = 30

• 13y = -30

• -1y = -78

• -13y = -78

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

When you solve these equations using the elimination method, which variable will be eliminated?

• The  x

• The  y

• The  z

• The unknown

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Order the algorithm (steps) to elimination

• add vertically

• Determine the variable to eliminate

• multiply equation(s) to have opposite coefficients, if necessary

• Align like terms vertically

• Solve for variable

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Which variable would be easiest to eliminate?

4x + 8y = 20

−4x + 2y = −30

• x because they have equal coefficients but opposite sign

• y because they have equal coefficients but opposite sign

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6