Let's Get Started

We are going to explore how to write an equation for a line using the slope and y-intercept.  You will also learn how to write an equation using point intercept form.  

TEKS Standards and Student Expectations

A(2) Linear functions, equations, and inequalities. The student applies the mathematical process standards when using properties of linear functions to write and represent in multiple ways, with and without technology, linear equations, inequalities, and systems of equations. The student is expected to:

A(2)(B) write linear equations in two variables in various forms, including y = mx + b, Ax + By = C, and y - y1 = m(x - x1), given one point and the slope and given two points

Resource Objectives

Given two points, the slope and a point, or the slope and the y-intercept, the student will write linear equations in two variables.

Essential Questions

Explain how you can create an equation in slope-intercept form when given two points.

Explain how you can create an equation in point-slope form when given two points.

Vocabulary

Writing Equations of a Line

Now that you have seen how to write linear equations when given the slope and y-intercept, you are ready to write linear equations!

Write an equation of the line with the given slope and y-intercept on your own paper. Click on the problem to see the answer.

Graphing Lines from Slope and y-Intercept

Now that you can write an equation in the form y = mx + b (slope-intercept form), you will find it is easy to graph the line.

View the video below to see how you can graph a line when you are given the slope and the y-intercept of the line.

 

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Source: 
Graphing an equation in slope-intercept form, Davitily, YouTube.

Practice:

Now it's time to practice graphing lines given the slope-intercept equation. Graph at least five new problems using this interactive website, in the form: y = mx + b

Instructions:

1. Click here to access the interactive website and graph in slope-intercept form.

2. Move A or B to the y-intercept.

3. Move the line to show the proper slope.

4. "You did it!" will appear if it is correct.

5. Click on "New Line" and repeat.

 

Writing Equations Given Two Points

Watch this video explaining how to write an equation for a line when you are given two points.

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Source: 
Find the Equation of a Line Given 2 Points, Intuitive Math, YouTube.

After viewing the video, write the equation for lines when you have been given two points and then check your answers by clicking on the problem.  

Student Practice

Now that you know how to write equations for lines, it's time to practice! Drag the equation to match the description of each problem into the correct box, and then click "Check" to check your answers.

Vocabulary Activity

Journal Activity