Elimination Steps

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

• subtraction or addition

• exponentiation

• division

• multiplication

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.

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

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

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.

• A

• B

• C

• D

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

Order the algorithm (steps) to elimination

• Determine the variable to eliminate

• Align like terms vertically

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

• Solve for variable

• add vertically

-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

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

• The  x

• The  y

• The  z

• The unknown