Lesson 2.7

Lesson 2.7

Equations of Proportional Graphs

By Reed Carbone

Definitions:

Proportional Equation: A proportional equation is of the form y = kx where k is the constant of proportionality.

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Equation of a line with y-intercept at the origin: The equation of a line when the y intercept is the origin (0,0) is y = mx.​

Rate of Change: Another name for slope.

Subject | Subject

Some text here about the topic of discussion

​Visuals:

How to write the equation of a proportional line:

Step 1: Find slope using rise over run





Step 2: Substitute 'm' into the equation y = mx

Multiple Choice

Is this graph proportional? If yes, what is the equation?

• It is not proporitional

• y = 10x

• y = 30x

• y = -10x

​Example: Find the slope of the line, then give the equation of the line

Multiple Choice

What is the equation of the line?

• y = 2x

• y = -2x

• y = x

• y = -x

How to Graph the equation of a line: y = 2x

Step 1: Plot a point










Step 2: Use slope as rise over run to find other points (minimum of 2 points needed)

Multiple Choice

Graph the line with equation $$y\ =\ -\frac{1}{2}x$$  

Multiple Choice

What is the equation of a line that goes through the origin?

• x = ym

• y = mx

• y = mx + b

• y = x

Fill in the Blanks

What is the equation of the line?

​Conclusion: Write 2 complete sentences about what you learned.