1. Chapter 4 Section 1
Formulas

2. Essential Question
Why would you want to be able to use substitution and manipulate variables to create equivalent formulas?

3. Substitute then solve vs. solve then substitute

4. Substitute then solve vs. solve then substitute
Example: The doctor told Jon that his BMI is 26. You don’t know how much he weighs, but can tell that he is about 6-ft tall. Being a good friends, you want to help him to be in healthier shape so you are going to exercise with him until he reaches the healthy BMI of What is your targeted weight loss for Jon?
Substitute then solve
Solve then substitute
Which method is more efficient?

5. Practice Manipulating Formulas
2x – y = 5 solve for y
2x – y = 5 solve for x
A= (1/2)bh solve for h
P = 2(l + w)

6. Manipulating Formula Hints
If it is adding or subtracting a monomial then it just switches signs when it moves to the other side of the equal sign.
Ex: x + 2y = 4 solve for x
Ex: y – 5x +12 = 3
If it is in the numerator then it moves to the denominator when moved across the equal sign
Ex: R = 2xy solve for y
If it is in the denominator then it moves to the numerator when moved across the equal sign
Ex: T= (abc)/(de) solve for a