1. Algebra 1 UNIT 2 Formulas and Functions
OBJECTIVES:
Solve formulas for different variables.
Solve equations for y so that y is a function of x.

2. Vocabulary Formula - an algebraic equation that
relates 2 or more real life quantities
Example: V = lwh (volume of a rectangle)
Non-Example: 2x + y = 3
Function Form – An equation solved for y so that y is a function of x.
Example: y = -7x + 3
Non-example: -4x + 2y = 5

3. #1 Distance Formula Solve for r in d = rt
d = rt Rewrite original formula
t t Isolate r by dividing both sides by t
Example problem:
If you ride your bike for 2.5 hours and travel 37.5 miles, what is your average speed?

4. #2 Interest Formula Solve I = prt for r.
I = prt Rewrite the original formula
pt pt Isolate r by dividing by pt
Example problem:
Find the rate when $2800 was invested for 4 years and earned $504 Interest.

5. #3 Area of a Prism Formula S - Ph = B Solve for B. S = 2B + Ph
S = 2B + Ph Write original formula
-Ph Ph Subtract Ph from each side
S - Ph = 2B
_____________ ______
Isolate B by dividing both sides by 2
S - Ph = B 2

6. Practice Problems 1) 2)

7. Rewriting an Equation in Function Form#4
Rewriting an Equation in Function Form
Rewrite the equation so y is a function of x y - 12x = 18
6y - 12x = Rewrite the original equation
+12x x Add 12x to both sides
6y = 12x + 18
______ ________ ________
Divide both sides by 6
y = 2 x + 3

8. Rewriting an Equation in Function Form#5
Rewriting an Equation in Function Form
Rewrite the equation so y is a function of x y + 2x = 15
-3y + 2x = Rewrite the original equation
-2x x Subtract 2x to both sides
-3y = -2x + 15
______ _______ _______
Divide both sides by -3

9. Practice Problems 1) 2)