Unit 5: Solving Systems- Elimination and Matrices

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

• (-7,0)
• (6,0)
• (-6,0)
• (7,0)

Tags

CCSS.HSA.REI.C.6

CCSS.8.EE.C.8B

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

Solve by elimination: 
4x + 8y = 20
−4x + 2y = −30

• (-1, 7)
• (-7, 1)
• (7, -1)
• (1, -7)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve by elimination:
2x - 3y = -6
-2x - 2y = 26

• (-9,-4)
• (9,4)
• (4,9)
• (-4,-9)

Tags

CCSS.HSA.REI.C.5

CCSS.HSA.REI.C.6

Solve by elimination:
x + 9y = 8
-6x - 9y = -3

• (1,-1)
• (1,1)
• (-1,1)
• (-1,-1)

Tags

CCSS.HSA.REI.C.5

CCSS.HSA.REI.C.6

Solve the system.  
5x + 8y = -12
3x + 5y = -7

• (1, -10)
• No solution
• (-4, 1)
• (1, 10)

Solving using Matrices:
When solving a system AX=B using inverse matrices, you use the equation:

• X=A^-1B
• B=X^-1A
• A=X^-1B
• X=B^-1A

Solving Systems:

Solve for x and y using inverse matrices

3x + 2y = 16

7x + y = 19

• (-2,5)

• (-2,-5)

• (2,-5)

• (2,5)

Solve the system of equations: 

• ( -1, 6, 1)
• ( 1, 6, -1)
• None of these
• ( -6, -1, 1)

Solve the system of equations: 
 $2x-3y-3z=-7$  
 $-2x+3y+4z=12$  
 $-3x+4y+2z=0$ 

• (2, 4, 5)

• (-2,-4, 5)

• (-2, 4, -4)

• None of these