Solve using Substitution Method System of Equations Solve using Substitution Method

Warm Up:

Homework Questions:

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

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

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

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

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

Example 2:

Answer for Example 2:

Example 3:

Answer for Example 3:

Example 4:

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?

Solve:

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?

Solve:

Practice: