Modeling Simultaneous Equations

Solve the simultaneous equations

x+y=5

x-y=1

• x=2, y=3

• x=3, y=2

• x=3, y=-2

• x=-3, y=2

Where do these two lines intersect?

• No solution
• (-2, 3)
• (3, -2)
• (2, 3)

Solve the system of equations using substitution:

-4x + 4y = 8

y = -2x - 10

• (-4, -2)

• (12, -34)

• (4, -18)

• (-2, -6)

Solve the system of equations using substitution:

y = 2x + 5

2x + 2y = 4

• (1, 7)

• (7, 1)

• (2, 9)

• (-1, 3)

What is the solution to the system?

8x + 4y = 12

y = -2x + 3

• (0,3)

• (3,0)

• No solution(parallel lines)

• Infinitely many solutions

Solve:

3x - y = 11

x + y = 5

• x = 4

  y = 1

• x = 4

  y = -1

• x = -4

  y = 1

• x = -4

  y = -1

Solve:

3x + 5y = 4

4x - 5y = -18

• x = -2

  y = 2

• x = -2

  y = -2

• x = 2

  y = -2

• x = 2

  y = 2

4x +  8y = 20
-4x + 2y = -30
Which variable will be eliminated?

• The  x
• The  y
• The  z
• The unknown

Solve by elimination:

4x+9y=28

-4x-2y=-28

• (-7,0)

• (6,0)

• (-6,0)

• (7,0)

Solve by elimination:

3x+7y=23

-3x-4y=-17

• No solution

• ARN

• (-3,3)

• (3,2)