Elimination Steps

In the elimination method, what operation is used to eliminate one variable?

• subtraction or addition

• exponentiation

• division

• multiplication

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

When using the elimination method, what happens if the coefficients of one variable are already the same in both equations?

• The elimination method is not necessary for that variable.

• The variable is automatically eliminated.

• The equations are already solved.

• The elimination method cannot be used in this case.

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

If you were to Eliminate for x, you would add straight down, then Divide. What is the value of y?

4x+ 9y = 28

-4x -y = -28

• y=0

• y=6

• -y=56

• y=2.8

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

If you were to Eliminate for x, you would add straight down, then Divide. Now that you have found the value of y=0, what is the equation if you were to substitute 0 in for the top equation?

• 4x+9(0)=28

• 4(0)+9y=28

• 4(0)+9(0)=28

• 4x+9y=0

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

If you were to Eliminate for x, would you need to multiply to cancel?

4x+ 9y = 28

-4x -y = -28

• Yes, The x numbers are NOT matching so we need to multiply.

• No. The x numbers ARE matching so we do not need to multiply.

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

• A

• B

• C

• D

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

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

• you cannot solve this using eliminiation

• cross out the 2x and 3x, because when you add them, they equal 0

• cross out the 2y and -2y because when you add them, they equal 0

• change to slope intercept form and graph

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Order the algorithm (steps) to elimination

• add vertically

• Solve for variable

• Align like terms vertically

• Determine the variable to eliminate

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

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