1. Chapter 3 –Systems of Linear Equations
3.2 – Solving Linear Systems by Substitution

2. 3.2 – Solving Linear Systems by Substitution
Today we will review:
Solving a system of linear equations in two variables by substitution

3. 3.2 – Solving Linear Systems by Substitution
Substitute (real-life) – Replace one thing with another
Substitute – Replace one variable with an expression containing the other variable

4. 3.2 – Solving Linear Systems by Substitution
Steps for Solving a Linear System by Substitution
Solve for one of the variables (the one with no coefficient (number in front))
Substitute the value from the step 1 into the other equation & solve for the other variable
Substitute the value from step 2 into the revised equation from step 1 and solve
Check the solution

5. 3.2 – Solving Linear Systems by Substitution
Example 1
Solve the system using substitution
y = 4x
-2x + y = -4

6. 3.2 – Solving Linear Systems by Substitution
Example 2
Solve the system using substitution
3x + 2y = 1
-2x + y = 4

7. 3.2 – Solving Linear Systems by Substitution
Example 3
In one week, a pizza restaurant sold 210 pizzas and made $ The price of a small is $12 and the price of a large pizza is $15. How many small pizzas and large pizzas were sold last week?

8. 3.2 – Solving Linear Systems by Substitution
HOMEWORK
Worksheet 3.2 Practice A