Solving Systems by Substitution Method

What is the solution to this system? (Use the substitution method.) 8x - 2y = 6 y = 3x

• (3, 9)

• (5, 2)

• (2, 3)

• (3, 2)

Solve the system of equations by using the Substitution Method.

y = 2x - 4

7x - 2y = 5

• (-1, -6)

• (-1, -8)

• (-2, 6)

• (1, -8),

Which answer has a correct next step for this system? (Read all three answers carefully before selecting one!)

• The variable is already isolated, so we've already solved the system.

• The variable is already isolated for y, so we substitute it in the second equation like this:

  2(6x) + 5y = 32

• The variable is already isolated for y, so we substitute it in the second equation like this:

  2x + 5(6x) = 32

Which answer has a correct next step for this system? (Read all three answers carefully before selecting one!)

• The variable is already isolated, so we've already solved the system.

• The variable is already isolated for y, so we substitute 3x + 5 in the first equation like this:

  3x + 4(3x + 5) = 3

• The variable is already isolated for y, so we substitute 3x + 5 in the second equation like this:

  3(3x + 5) + 4y = 3

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

Solve the following systems of equations using substitution:

2y + x = -15

x = 3y

• (-3, -9)

• (-9, -3)

• (-3, 9)

• (9, -3)

Which answer has a correct first step for this system:

• The variable is already isolated, so we've already solved the system.

• The variable is already isolated for y, so we substitute it in the first equation and solve for x

  3x + 3(3x + 5) = 3

• Free sha vaca doo

• The variable is already isolated for y, so we substitute it in the second equation and solve for x

  y = 3(3x + 3y) = 3

Solve this system of equations. 
y = 2x + 1
y = 4x - 1

• (1,3)

• (-1,-3)

• (-1,3)

• (3,1)

Solve the system of equations.

• (-6, 1)

• (-12, -12)

• (1, -6)

• No solution

• Infinite solutions

What is the solution?
(Hint:  Both lines are graphed over each other)

• One Solution

• No solution

• Infinitely Many Solutions