# Graphing 19 - Writing Equations 2

Taught by YourMathGal
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Part of video series
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Lesson Summary:

This lesson covers two methods for writing the equation of a line when you know the slope and a point on the line. The first method involves writing the equation in y=mx+b form and solving for b, while the second method involves using the point-slope formula. The point-slope formula allows you to plug in the slope, as well as the x and y coordinates of the point, to get the equation in point-slope form. This can then be simplified to the slope-intercept form if needed.

Lesson Description:

This video covers how to find the equations of lines if you know the slope and a point. Goes over the point-slope formula. This is part 19 of a series of videos about graphing lines.

More free YouTube videos by Julie Harland are organized at http://yourmathgal.com

Questions answered by this video:
• What is the point-slope form of a line?
• How do you write an equation of a line in point-slope form?
• When is the point-slope form useful for writing an equation?
• How do you find the equation of the line with slope 2 that passes through (-4, 5)?
• How can you re-write an equation in point-slope form in slope-intercept or standard form?
• How do you write the equation of the line with slope -1/3 that passes through (-6, 9) by using the point-slope form of a line?
• How can you find the equation of a line with a given slope that passes through a given point by graphing the line?
• How can you use the slope and a point to graph a line, find the y-intercept, and write the equation of the line?
• How do you write the equation of a line using point-slope form if you are given the slope and a point on the line?
• #### Staff Review

• Currently 4.0/5 Stars.
This video explains a second method for writing the equation of a line if you are given the slope of the line and a point the line passes through. The point-slope form of a line is used in this lesson. This method works very well for this setup of having a point and a slope. Graphing the point and using the slope to find the y-intercept is also explained.