Solve a System of Equations by Elimination

Solve the system of equations.

• (3, -1)

• (-1, -3)

• (-1, -1)

• (-1, 3)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve the system of equations.

• (5, 4)

• (4, 5)

• (-3, -12)

• (5, 16)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

What is the best method to use?

−4x − 2y = −12

4x + 8y = −24

• Graphing because both equations are in slope-intercept form.

• Substitution because a variable is defined

• Elimination because the equations are in standard form.

• Any method would be equally as "easy"

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

What is the proper way to set up the equation to begin solving?

y = 6x − 11

−2x − 3y = −7

• -2(-11) -3y= -7

• -2(6x-11) -3y = -7

• -2x -3(11) = -7

• -2x - 3(6x-11)= -7

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve the system of equations.

3x - y = 7

y = -2x +3

• (-1,2)

• (5,4)

• (4,5)

• (2,-1)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

When using the elimination method, what is the first step to eliminate one variable?

• Multiply one or both equations by a constant

• Subtract one equation from the other

• Divide one equation by a constant

• Add one equation to the other

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve the following system of equations using the elimination method: 2x + 3y - z = 5 3x - 2y + 4z = 7 4x + y + 2z = 3

What is the elimination method used for in solving 3-variable systems?

• To substitute variables in a system of equations

• To graphically represent a system of equations

• To find the determinant of a matrix

• To eliminate variables in a system of equations

 4x + 8y = 20
-4x + 2y = -30

• (-7,1)

• (2,-5)

• (-2,5)

• (7,-1)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve by elimination
-6x + 5y = 1
6x + 4y = -10

• (1,-1)

• (0,-1)

• (1,1)

• (-1,-1)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6