# Lesson 11

Equations of All Kinds of Lines

Let’s write equations for vertical and horizontal lines.

### Problem 1

Suppose you wanted to graph the equation \(y=\text-4x-1\).

- Describe the steps you would take to draw the graph.

- How would you check that the graph you drew is correct?

### Problem 2

Draw the following lines and then write an equation for each.

- Slope is 0, \(y\)-intercept is 5
- Slope is 2, \(y\)-intercept is -1
- Slope is -2, \(y\)-intercept is 1
- Slope is \(\text-\frac{1}{2}\), \(y\)-intercept is -1

### Problem 3

Write an equation for each line.

### Problem 4

A publisher wants to figure out how thick their new book will be. The book has a front cover and a back cover, each of which have a thickness of \(\frac{1}{4}\) of an inch. They have a choice of which type of paper to print the book on.

- Bond paper has a thickness of \(\frac{1}{4}\) inch per one hundred pages. Write an equation for the width of the book, \(y\), if it has \(x\) hundred pages, printed on bond paper.
- Ledger paper has a thickness of \(\frac{2}{5}\) inch per one hundred pages. Write an equation for the width of the book, \(y\), if it has \(x\) hundred pages, printed on ledger paper.
- If they instead chose front and back covers of thickness \(\frac{1}{3}\) of an inch, how would this change the equations in the previous two parts?