Solving Systems of Equations Using Elimination

• (-9, 9)
• (9, 9)
• (9, -9)
• (7, 9)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

• (8, -10)
• (-10, 8)
• (3, 8)
• (10, 8)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

• (0, -1)
• Infinitely Many Solutions
• (0, 1)
• (-1, 0)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

• (-4, -7)
• (5, 7)
• (4, 7)
• (4, -7)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

• (2, -8)
• (8, -2)
• (2, 1)
• (2, 8)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve the following using elimination. x-y=11 2x+y=19

• (10,-1)

• (-1,10)

• (-1,-10)

• (-10,-1)

Answer explanation

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

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

• Rewrite the equations so the variables are all on the same side and line up the like terms.

• Get both equations in slope-intercept form.

• Get both equations equal to zero.

• Put the x terms first.

Answer explanation

We need all of the variables on the same side so that we can eventually add the left side of both equations together and add the right side of both equations together.

If the variables aren't on the same side of the equal-sign, then we can't combine like terms.

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

To eliminate a variable in the system, should you add the equations or subtract the equations?

• Add

• Subtract

• Neither

Answer explanation

We want to add the equations together in order to eliminate one of the variables. We have opposite terms (3x and -3x) that will "cancel/zero out" (be eliminated) when we add the equations together.

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Which variable would be easiest to eliminate?

• x

• y

• Neither

Answer explanation

The terms with x in them have opposite coefficients (4x and -4x), so they will be the easiest to eliminate when we add the equations together.

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve using Elimination:

5x + y = 9

10x − 7y = −18

• (4, -11)

• (1, 4)

• (-1, 14)

• (-4, 29)

Answer explanation

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6