1. Solving a system of linear equations… You’ve already learned: We have to learn: 1. Graphing2. Substitution 3. Elimination Solving Linear Systems by Substitution 7.2 Objectives for Today: 1.Solve a system of equations by substitution 2.Solve systems from the real world

2. When we say to solve for one variable…Which is the best variable to use for substitution? Solve the System by Substitution Solve a system by substitution: 1.Solve for one of the variables and star it.  Hint: Look for the variable that is already alone OR easy to isolate. 2. Substitute this expression into the other equation. 3. Solve for the only variable. 4. Substitute this value into the starred equation. 5. Clearly state your answer as an ordered pair. 6. Check the answer. Here’s Our Steps:

3. Solve the system by substitution. Solve a system by substitution: 1.Solve for one of the variables and star it. 2.Substitute this expression into the other equation. 3.Solve for the only variable. 4.Substitute this value into the starred equation. 5.Clearly state your answer as an ordered pair. 6.Check the answer. (-1, 0) Example 1 Solve the System by Substitution

4. Solve the system by substitution. (2, 4) Example 2 Solve the System by Substitution Solve a system by substitution: 1.Solve for one of the variables and star it. 2.Substitute this expression into the other equation. 3.Solve for the only variable. 4.Substitute this value into the starred equation. 5.Clearly state your answer as an ordered pair. 6.Check the answer.

5. Solve the system by substitution. (9, 2) Example 3 Solve the System by Substitution Solve a system by substitution: 1.Solve for one of the variables and star it. 2.Substitute this expression into the other equation. 3.Solve for the only variable. 4.Substitute this value into the starred equation. 5.Clearly state your answer as an ordered pair. 6.Check the answer.

6. Solve the system by substitution. (2, 2) Example 4 Solve the System by Substitution Solve a system by substitution: 1.Solve for one of the variables and star it. 2.Substitute this expression into the other equation. 3.Solve for the only variable. 4.Substitute this value into the starred equation. 5.Clearly state your answer as an ordered pair. 6.Check the answer.

7. In one day, the Baseball Hall of Fame in Cooperstown admits 321 adults and children and collects $1590. The price of admission is $6 for an adult and $4 for a child. How many adults and how many children were admitted to the museum that day. 153 adults & 168 children Example 5 Real Life Linear System

8. Solve the system of equations by substitution. Exit Slip To be completed before leaving…

9. 7.2 Practice Worksheet Back of Notes!