Day 8 – Linear Equations and Slope

Today we begin to study the connection between things we draw (geometry) and equations that describe them (algebra).  This connection is possible because of the simple but brilliant idea of plotting points — here is a review of plotting.

In this class, we will focus on equations of lines.  An equation of a line, or linear equation, is an equation that can be written in the form Ax+By=C, called standard form.  Another useful form of linear equations that you may be familiar with is y=mx+b, or slope-intercept form.

There are a lot of resources available on the internet and elsewhere about equations of lines.  Here are a few, grouped according to the major topics and types of problems.

We begin with an equation of a line, and draw the graph by finding solutions and plotting points.

One of the key pieces of information that we use in studying lines is the slope.  If you need a review of finding the slope of a line, here is a video with a good explanation.

We will be practicing finding equations for lines.  These types of problems can vary a bit depending on what information you are given at the start.  The following series of videos cover several of the possibilities.

1. Find equation of a line based on the slope and one point (the y-intercept): http://youtu.be/AqFwKecNaTk

2. Find the equation of a line based on the slope and a point (not the y-intercept):

3. Find the equation of a line based on two points: http://youtu.be/XMJ72mtMn4Y

Finally, we consider parallel and perpendicular lines.

 

 

 

7 Responses to Day 8 – Linear Equations and Slope

  1. sbailey says:

    proff. halleck
    i remember slope and y-intercept but today in class i was introduce to new things that included slopes and linear equations was confused a bit

  2. Rebecca Kogan
    Professor Halleck

    Linear equations is pretty much easy when you know what to plug in into which equation. I found the videos on this page really helpful to help me further understand the topic.

  3. brina92 says:

    Linear equations on a graph was giving me some difficulty, because i am not so well with graphs. That’s why math zone homework problems were harder even with guided help, though some i were able to figure out

  4. I love slope and plotting line intercepts. Just another review. Thanks though.

  5. perez92 says:

    John
    Prof. Reitz
    I never liked slopes and the formulas associated with them but maybe its because i didn’t understand them but these lessons and videos refresh and make it alot simpler to understand, doesn’t mean i like them now but i understand it better..

  6. awiltshire says:

    Pro. Halleck

    It was okay, not into slopes but I somewhat understood the linear equations.

  7. Pingback: Who needs me, anyway? Khan Academy and the re-imagining of education | CUNYMath Blog

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