Transcript 3.7 Formulas and Functions

3.7 Formulas and Functions
Vocabulary
• Formula - an algebraic equation
that relates 2 or more real life
quantities
• Function Form -a two-variable
equation written so that one of its
variables is isolated on one side of
the equation
Ex) Rewrite 7x - y = 3 so that y is a
Function of x is rewritten as
y = -7x + 3
Distance Formula
• Solve for r in d = rt
d = rt
Rewrite original formula
t
t
Isolate r by dividing both sides by t
d
r
Simplify
t
If you ride your bike for 2.5
hours and travel 37.5 miles,
what is your average speed?
Interest Formula
Solve I = prt for r.
I = prt
Rewrite the original formula
pt pt
Isolate r by dividing by pt
I/pt = r
Simplify
•Find the rate when $2800
was invested for 4 years and
earned $504 Interest.
Solving Formulas
•
Use the formula for the area of a
right prism. Solve for B.
S = 2B + Ph
Write original formula
-Ph
- Ph
Subtract Ph from each side
S - Ph = 2B
Simplify
________
________
2
2
Isolate B by dividing both sides by 2
S - Ph = B
2
Simplify
Rewriting an Equation
in Function Form
Rewrite the equation so y is a function of x.
6y - 12x = 18
6y - 12x = 18
Rewrite the original equation
+12x +12x Add 12x to both sides
6y = 18 + 12x Simplify
______
6
y
______________________
6
= 3+2x
Divide both sides by 6
Simplify