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Equations of parallel and perpendicular lines with Desmos

Last updated about 6 years ago

6 questions

Open the website:  
https://www.desmos.com/calculator

We want to answer the question:    
 
What is the equation of the line that is parallel to the line y=-3/4x+2 that goes through the point (-4, 2)?

On desmos.com, graph the original equation by typing  y=-3/4x+2  in the first line.

On desmos.com, graph the point by typing (-4, 2) in the second line.

It should look like this.

1

Our new line needs to be parallel to the original line. Parallel lines have the SAME slope. What is the slope of the new line? Type that on line #3 in desmos.

1

To write the equation of the line, we need two things. What is one?

1

What is the other one?

Start at the point and count down 4, over 3 until you land on the y-intercept.

1

What is the y-intercept

Add the y-intercept to your equation on line #3.  

1

Is your equation parallel to the original line (y=-3/4x+2)

1

Is your y intercept on -1?