Steps to Solving Systems by Elimination

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

2x + 2y = -2

3x - 2y = 12

• 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

4x +  8y = 20

-4x + 2y = -30

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

The coefficients of the eliminated variable must be _____.

• opposites

• the same

• distinct

• does not matter

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Look for ____ when determining which variable to eliminate. Select all that apply

• same coefficeints with opposite signs

• easy numbers to multiply to (common factors)

• different coefficients

• vertical alignment of like terms

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

To find the second variable, substitute the x or y you solved for into one of the ____.

• original equations

• one of the manipulated equations

• the top equation, always

• the bottom equation, always

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Order the algorithm (steps) to elimination

• Solve for variable

• Align like terms vertically

• Determine the variable to eliminate

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

• add vertically

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