Solving Systems Algebraically

Solve using substitution.

• (1,3)

• (3,-1)

• (7,3)

• (3,1)

Solve using elimination.

• (4,5)

• (3,4)

• (5,4)

• (5,-4)

Solve the system.

• (3,7)

• (5,7)

• (6,6)

• (3,6)

Solve the system.

• (9,11)

• (-2,3)

• (3,-2)

• (3,11)

The difference between Alex's age and Erin's age is 7. The sum of their ages is 27 years. How old are Alex and Erin. If x=Erin's age and y=Alex's age, choose the system that matches the situation.

• x - y = 27

  x + y = 7

• x - y = 7

  x + y = 27

• x + y = 7

  x + y = 27

• x + y = 34

  x - y = 20

Christian originally ordered 4 boxes of blue T-shirts and 3 boxes of red T-shirts, which cost a total of $134. After he ran out, Christian spent $120 on 3 boxes of blue T-shirts and 3 boxes of red T-shirts.

Let x = the price of a box of blue T-shirts

Let y = the price of a box of red T-shirts

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

If a system of equations has no solution, what does the graph look like?

• intersecting lines

• parallel lines

• the same line

Solve by elimination:

4x+9y=28

-4x-y=-28

• (-7,0)

• no solution

• (-6,0)

• (7,0)

Solve the system of equations.

• (-6, 1)

• (-12, -12)

• No solution

• Infinite solutions

What is the solution to this system?

2x + 3y = 4

y= 5x - 27

• (5,-2)

• (5, 2)

• (2,3)

• (3,2)