# Solve Systems By Substitution (Easy Version)

Systems of Equations

# Solve Systems By Substitution (Easy Version)

Created 3 years ago

Duration 0:05:53
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Slide Content
1. ### Slide 1 - Objective

• The student will be able to:
• solve systems of equations using substitution.
• SOL: A.4e
• Designed by Skip Tyler, Varina High School
• Modified by Mr. Burns
2. ### Slide 2 - Solving Systems of Equations

• These notes show how to solve the system algebraically using SUBSTITUTION.
3. ### Slide 3

• Solving a system of equations by substitution
• Step 1: Solve an equation for one variable.
• Step 2: Substitute
• Step 3: Solve the equation.
• Step 4: Plug back in to find the other variable.
• Step 5: Check your solution.
• Pick the easier equation. The goal
• is to get y= ; x= ; a= ; etc.
• Put the equation solved in Step 1
• into the other equation.
• Get the variable by itself.
• Substitute the value of the variable
• into the equation.
• Substitute your ordered pair into
• BOTH equations.
4. ### Slide 4 - 1) Solve the system using substitution

• x + y = 5
• y = 3 + x
• Step 1: Solve an equation for one variable.
• Step 2: Substitute
• The second equation is
• x + y = 5x + (3 + x) = 5
• Step 3: Solve the equation.
• 2x + 3 = 5
• 2x = 2
• x = 1
5. ### Slide 5 - 1) Solve the system using substitution

• x + y = 5
• y = 3 + x
• Step 4: Plug back in to find the other variable.
• x + y = 5
• (1) + y = 5
• y = 4
• Step 5: Check your solution.
• (1, 4)
• (1) + (4) = 5
• (4) = 3 + (1)
• The solution is (1, 4). What do you think the answer would be if you graphed the two equations?
6. ### Slide 6 - Which answer checks correctly?

• 3x – y = 4
• x = 4y - 17
• (2, 2)
• (5, 3)
• (3, 5)
• (3, -5)
7. ### Slide 7 - 3) Solve the system using substitution

• x = 3 – y
• x + y = 7
• Step 1: Solve an equation for one variable.
• Step 2: Substitute
• The first equation is