Solving Systems of Equations by Elimination and Substitution

Solve by elimination:

7x+y=-9

-3x-y=5

• No solution

• (1,8)

• (-1,-3)

• (-1,-2)

Christian had brochures printed for a new business venture. Christian originally ordered 4 boxes of black-and-white brochures and 3 boxes of color brochures, which cost a total of $134. After those ran out, Christian spent $120 on 3 boxes of black-and-white brochures and 3 boxes of color brochures. Which system represents this situation?

• x+y=134
  x+y=120

• 3x+3y=134
  4x+3y=120

• 4x+3y=134
  3x+3y=120

• 7xy=134
  6xy=120

The talent show committee sold a total of 530 tickets in advance. Student tickets cost $3 each and the adult tickets cost $4 each. If the total receipts were $1740, how many of each type of ticket were sold?

• S + A = 530
  3S + 4A = 1740

• S + A = 530
  4S + 3A = 1740

• S + A = 1740
  3S + 4A = 530

• S + A = 1740
  4S + 3A = 530

• 2x + 6(-5x) = -3

• 2x - 5x = -3

• y + 6(-5y) =-3

• 2(-5x) + 6y = -3

3x + y = –14

–2x – y = 9

Which method would be best for solving this system?

• Substitution

• Elimination/Matrices

Solve the following systems of equations using substitution:

2y + x = -15

x = 3y

• (-3, -9)

• (-9, -3)

• (-3, 9)

• (9, -3)

Solve this system by substitution.

• (1, -4)

• (1, 4)

• (-4, -7)

• (-7, -4)

The first step in solving using the substitution method is __________.

• get x by itself

• get y by itself

• get either variable by itself

• add the equations together

How many solutions will this system have? 

• No solution

• One Solution

• I Don't Know

• Infinitely Many Solutions

Solve by matrices.

4x+9y=28

-4x-y=-28

• (-7,0)

• (6,0)

• (-6,0)

• (7,0)