Solve System of Equations Using Elimination and Substitution

Solve using substitution:

y = -6x + 5

-2x + y = 5

• (-3, -6)

• (-6, 3)

• (0, 5)

• (-3, 5)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve with substitution:

y = -2x + 18

y = 8

• (5, 8)

• (-5, 8)

• (2, 8)

• (-2, 8)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve by elimination
-2x + 6y = 16
-4x - 3y = 2

• (2,2)

• (-2, -2)

• (-2,2)

• (2,1)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

You can solve systems using these methods:

• graphing, substitution, and elimination

• rearranging, thinking, and guessing

• only by graphing

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve by elimination:
7x+y=-9

-3x-y=5

• No solution

• (1,8)

• (-2,-3)

• (-1,-2)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Which method may be fastest if both equations are in standard form with the x's and y's lined up?

• graphing

• substitution

• elimination

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve with substitution

x = -3y - 8

x - 2y = -3

• (5, -1)

• (-5, 1)

• (-5,-1)

• (1,-5)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

What variable do you eliminate, and what do you multiply the equation(s) by?

• You eliminate x, and multiply the top equation by 11

• You eliminate y, and multiply the top equation by 7

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve using elimination. 
−4x − 4y = 0
4x + 4y = 0 

• (−6, −4) 

• Infinite number of solutions  

• (−6, 10) 

• (6, 4) 

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

-4x - 6y = 6
4x + 6y = -4

• no solution

• (2,0)

• (-4,0)

• (0,0)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6