Name ___________________________________________ Date __________________ Hour _______________

C-04 Writing Equations of Lines Part 2

Tables and Word Problems

Helpful Formulas: 𝑚 =𝑦2−𝑦1

𝑥2−𝑥1 𝑦 = 𝑚𝑥 + 𝑏 𝑦 − 𝑦1 = 𝑚(𝑥 − 𝑥1)

Warm-Up: For 1 and 2, find the slope.

1. 2.

For 3 and 4, write the equation of the line that represents each problem.

3. 4. Line that contains (3, −2) and (9,2)

x y

-3 4

0 3

9 0

All tickets for a concert are the same price. The ticket

agency adds a fixed fee to every order. A person who

orders 5 tickets pays $93. A person who orders 3 tickets

pays $57.

Remember the two things we need to create a line:

If we are not given a slope, that is the first thing we have to find. Then we can use the slope, and any

given point, to find the equation of the line.

Remember that you can choose if you want to use point-slope form or slope-intercept form to create

your equation! Either way, your final answer should always be in _________________________________.

Remember to keep an eye out for sneaky “b”s!

The two special lines that follow their own rules are…

-Horizontal lines, which have a slope of ________ and have the equation _____________

-Vertical lines, which have a slope of ____________________ and have the equation ___________

Example 1: What is the equation of the line from the table?

Example 2: Find the equation of the line represented by the table:

Example 3: Find the equation of the line represented by the table:

X y

-3 4

0 3

9 0

x y

2 -4

2 -5

2 -6

2 -7

x y

-18 -13

-16 -12

-4 -6

-2 -5

Example 4: Find the equation of the line represented by the table:

There are 3 types of word problem set-ups:

1. Given a slope and a “b” (think of it as a starting point or an initial fee)

2. Given a slope and a data point

3. Given two data points

Example 5: A plane loses altitude at the rate of 5 meters per second. It begins with an altitude of

8500 meters. The plane’s altitude is a function of the number of seconds that pass.

Use your equation to find out how much time will pass before the plane will land (hint: what is the

altitude when the plane lands?)

Example 6: An internet service provider charges $18 per month plus an initial set –up fee. One

customer paid a total of $81 after 2 months of service. Write an equation modeling this situation.

How much does it cost after 5 months of service?

x y

2 -10

5 -10

7 -10

10 -10

Example 7: Your gym membership costs $33 per month after an initial membership fee. You paid a

total of $228 after 6 months. Write an equation that gives you the total cost related to the months of

your gym membership.

Find the total cost after 9 months.

Example 8: All tickets for a concert are the same price. The ticket agency adds a fixed fee to every

order. A person who orders 5 tickets pays $93. A person who orders 3 tickets pays $57. Write an

equation relating the total cost to the number of tickets purchased.