Applications of Linear Equations
Warm ‐ Up
9/18/13
1. Write the equation of a line parallel to y = - 2x + 3
and passes through (-3, 5)
September 18, 2013
1. Suppose you receive $100 for a graduation present, and you deposit it in
a savings account. Then each week thereafter, you add $5 to the
account but no interest is earned. The amount in the account is a
function of the number of weeks that have passed.
a. Write an equa on for the amount y you have a er x weeks.
b. Use your equa on to find when you will have $310 in the account.
2. Find the slope of a line perpendicular to
3x + 5y = 7
Sep 17-8:04 PM
2. An airplane 30,000 feet above the ground begins descending at the
rate of 2000 feet per minute. Assume the plane continues at the
same rate of descent. The plane’s height and minutes above the
ground are related to each other.
Sep 17-9:44 PM
3. Nick is given $50 to spend on a vacation. He decides to spend $5 a day. The
amount Nick has left and the number of days are related.
a. Define a variable for the number of days and amount of money Nick has le . Write
and equa on for Nicks spending.
a. Write an equa on to model the situa on.
b. Use your equa on to find out when Nick will have $15 le .
b. Use your equa on to find the al tude of the plane a er 5 minutes.
Sep 17-9:48 PM
4. The Freshman class holds a car wash to raise money for a local charity.
A local merchant donates all of the supplies. A car wash costs $5 per car and
Sep 17-9:50 PM
5. Larry runs at an average rate of 8 mi/h. He walks at an average
rate of 3 mi/h.
$6.50 per van or truck.
a. Define a variable for the number of cars.
Define a different variable for the number of vans or trucks.
b. Write an equa on in standard form to relate the number of cars and vans or trucks
the students must wash to raise $800.
Sep 17-9:53 PM
a. Define a variable for me spent walking.
Define a different variable for me spent running.
b. Write an equa on in standard form to relate the mes he could spend running and
walking if he travels a distance of 15 mi.
Sep 17-9:55 PM
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Applications of Linear Equations
6. Suppose you are preparing a snack mix. You want the total protein from
peanuts and granola to equal 28 grams. Peanuts have 7 grams of protein per
ounce, and granola has 3 grams of protein per ounce.
September 18, 2013
7. You are sent to the store to buy sliced meat for a party. You are told to
get a roast beef and turkey, and you are given $30. Roast beef is
$4.29/lb and turkey is $3.99/lb. Write an equation in standard form to
relate the pounds of each kind of meat you could buy at the store with $30.
a. Write an equa on for the protein content of your mix.
b. Graph your equa on. Use your graph to find how many ounces of
granola you should use if you use 1 ounce of peanuts.
Sep 17-9:57 PM
Sep 17-9:59 PM
8. Suppose your school is having a talent show to raise money for new music
supplies. You estimate that 200 students and 150 adults will attend. You also
estimate $200 in expenses. Write an equation to find what ticket prices you
should set to raise $1000.
Sep 17-10:01 PM
Sep 18-9:04 AM
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