Systems of Linear Equations

There are 50 donkeys and chickens on a far.  There are a total of 174 legs.  Which system below can be used to figure out how many of each animal the farm has?

• d + c = 174
  4d + 2c = 50

• d + c = 50
  4d + 2c = 174

• d + c = 50
  2d + 4c = 174

• d + c = 174
  2d + 4c = 50

At a restaurant the cost for a breakfast taco and a small glass of milk is $2.10. The cost for 2 tacos and 3 small glasses of milk is $5.15. If a system of equations is written, which would be the correct representation of the 2 variables?

• t: # of tacos

  m: # of glasses of milk

• t: Cost of each taco

  m: Cost of each glass of milk

• t: total cost

  m: # of food items

• t: Cost of each glass of milk

  m: Cost of each taco

Solve the following system by graphing.  What is the solution?

• (-4, 2)

• (4, 2)

• (2, -4)

• (2, 4)

Solve the following system by substitution.  What is the solution?

• (1, -2)

• (-2, 1)

• (-4, 1)

• (2, 1)

Solve the system using any method. 
−4x − 4y = 0
4x + 4y = 0 

• (−6, −4) 

• Infinite number of solutions  

• No solutions

• (6, 4) 

Solve for x and y using any method we've learned!
y = 2x + 1
y = 4x - 1

• (1,3)

• (-1,-3)

• (-1,3)

• (3,1)

Solve the system of equations below:
9x - 4y = 1
-3x + 8y = -47

• (3, -7)

• (-3, 7)

• (-3, -7)

• (-7, -3)

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

• (-7,0)

• (6,0)

• (-6,0)

• (7,0)

Solve by elimination:
9x-4y=7

x-4y=-17

• (-1,5)

• (-7,5)

• (7,5)

• (3,5)

Solve by elimination:
7x-9y=29

7x+2y=-15

• (-4,-1)

• (-1.-4)

• (-1,4)

• (-1,6)