1. Solve using Substitution Method
System of Equations
Solve using Substitution Method

2. Warm Up:

3. Homework Questions:

4. Review:  Graphing  Technology  Solutions to the system
 How do we know by looking at graph or equations

5. What is substitution? Replacing your variable with an expression
Example:
F(x) = 2x + 3 evaluate at x =-2.
What do you do

6. Substitution Method: When is it best?
If one equation has a variable isolated or can be easily isolated
Why do we need to know this method?
To Find the solution to the system
How do we solve using this method
Use a t-chart for organization and find the two variable first

7. Steps: 1) Place both equations in box #1
2) Place the equation with an isolated variable (or the easily isolated variable) in box #2
3) Isolate a variable in the equation in box #2
4) Place the second (unused) equation in box #3
5) Substitute the equation from box #2 into the appropriate variable in box #3
6) Solve the equation in box #3
7) Copy the equation from box #2 into box #4
8) Substitute your answer from box #3 into the equation in box #4
9) Solve the equation from box #4
10) Write your ordered pair

8. Example 1: Solve for one equation Put both equation here
Plug in the value found to the above equation
Put the other equation here Replace the variable.
Solve

9. Example 2:

10. Answer for Example 2:

11. Example 3:

12. Answer for Example 3:

13. Example 4:

14. Real World Applications Example:
Maribel has $1.25 in her pocket. The money is in quarters and dimes. There are total of 8 coins. How many quarters and dimes does Maribel have in her pocket?

15. Solve:

16. Real World Applications Example:
Fabulously Fit offers memberships for $35 per month plus a $50 enrollment fee. The fitness Studio offers memberships for $40 per month plus a $35 enrollment fee. In how many months will the fitness clubs cost the same? What will that cost be?

17. Solve:

18. Practice: