Solving Systems of Equations by Elimination and Three Variables

Solve the system by elimination.

−6x + 6y = 0

9x − 8y = 4

• (4, −9)

• Infinite number of solutions

• (−9, 4)

• (4, 4)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

________________ are two or more equations that have the same variables and work together.

• graphing lines

• elimination method

• system of equations

• table

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

What is the first step in solving a system of equations by elimination?

• Get both equations in standard form and line up the like terms.

• Get both equations in slope-intercept form.

• Get both equations equal to zero.

• Put the x terms first.

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve by elimination:
4x+9y=28
-4x-y=-28

• (-7,0)

• (6,0)

• (-6,0)

• (7,0)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve the system using elimination.

Solve the system using elimination.

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

Which of the following could be a correct first step in solving the system shown? Select all that apply.

• Multiply the first equation by 2, then add the result to the third equation.

• Multiply the second equation by 2, then add the result to the third equation.

• Add the first and second equation.

• Add the first and third equation.

• Add the second and third equation.

Solve the system of equations using the elimination method:

3x + 2y - z = 6

2x - y + 3z = 4

4x + 3y + 2z = 9

• x = 4/5, y = 2, z = -3/5

• x = 0, y = 0, z = 0

• x = -2/3, y = 1/2, z = 1/4

• x = 1, y = 3, z = 2

Solve by elimination:

7x - 9y = 29

7x + 2y = - 15

• (-4,-1)

• (-1.-4)

• (-1,4)

• (-1,6)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6