Bell Work:
1. A picture frame originally priced at $14.89
is on sale for 40% off. What is the discounted
price?
2. A shirt is $14.99 before sales tax. If sales
tax is 7%, what is the final price?
3. Your items total $45.56 before discounts
and tax. You have a 20% off coupon and
sales tax is 6%. What is your final amount
owed?
Homework Quiz:
Show all work and circle your answer.
41. A group of girls are shopping for dresses to wear
to the spring dance. One finds a dress priced $75 with
a 20% discount. A second girl finds a dress priced $85
with a 30% discount.
a) Find the amount of the discount for each dress.
b) Which girl is getting the better price for the dress?
42. In 1995, there were 73,567 youth softball teams. By
2007, there were 86,049. Determine the percent of
increase.
2.8 Literal Equations and Dimensional Analysis
Objectives: I can solve equations for given variables.
I can use formulas to solve real-world problems.
Lots of equals have more than one variable. Right now we only know how to solve
equations with one variable. However, we can solve for a specified variable when we
have an equation with more than one variable.
Example #1

Solve 4m – 3n = 8 for m.
This means we want m = __________.

Solve 15 = 3n + 6p for n.

Solve 28 = t(r + 4) for t.
We often want to use this for formulas, depending on what variable we are solving for.
Example #2

The formula for the circumference of a circle is C = 2πr. Solve this formula for r.

If the circumference is 32ft, what is the radius?
We can use formulas to do _____________________ or ________________.
This allows us to convert from one unit to another.
Strategy: multiply by fractions that equal one, so we don’t change the value we only
change the units.
Example #3

A 10K run is 10 kilometers long.
If 1 meter = 1.094 yards and 1 mile = 1760 yards, find the length of the race in
miles.

A car travels a distance of 100 feet in about 2.8 seconds. What is the velocity of
the car in miles per hour? Round to the nearest whole number.