3.3 Substitution Method

3.3 Substitution Method

Objective: Students will solve systems of equations by using substitution method at 70% mastery.

Steps for Substitution Method:

Step 1: Solve one of the equations for either x = or y = .

Step 2: Substitute the solution from step 1 into the second equation.

Step 3: Solve this new equation.

Step 4: Solve for the second variable

Multiple Choice

The solution (x, y) to a system of equations is the point where they...?

• Run off the graph

• Don't touch

• Intersect

• Exist

Multiple Choice

What is the solution?

• (1, -1)

• (-1, 1)

• (0, -2)

• (0, 1)

Multiple Choice

Solve the system by elimination.

−4x − 4y = 0

4x + 4y = 0

• (−6, −4)

• Infinite number of solutions

• No Solution

• (6, 4)

• (0,0)

Video for 3.3 Substitution Method

Video 1:

https://www.youtube.com/watch?v=xzuouSZ69XU

Video 2:

https://www.youtube.com/watch?v=-mZZ6iPwQpE&t=8s

Multiple Choice

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

• get x by itself

• get y by itself

• get either variable by itself in one equation

• add the equations together

Multiple Choice

Solve the system using substitution method.

y = -6

-3x - 6y = 24

• (6, 6)

• (6, -6)

• (4, -6)

• (-6, 4)

Multiple Choice

Solve the following system using substitution:

 $y=-3x+5$  

 $5x-4y=-3$  

•  $\left(1,\ 2\right)$  

•  $\left(1,\ 5\right)$  

•  $\left(2,\ 5\right)$  

•  $\left(5,\ 1\right)$