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Please can you help explain how to do a straight line graph

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user7500010 | Student | eNotes Newbie

Posted May 19, 2013 at 3:44 PM via web

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Please can you help explain how to do a straight line graph

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crmhaske | College Teacher | (Level 3) Associate Educator

Posted May 19, 2013 at 4:28 PM (Answer #1)

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The steps taken to plot a straight line are dependent on what information has been provided.

Given a table of data, you can simply plot the points and "connect the dots", but we aren't always given a table of data.  Sometimes we need to construct the equation for the line, defined as y=mx+b, first.

For example, Jimmy's height for the past 8 years has changed linearally.  The last time he was measured he was 70 inches tall.  Each year he grows 1 inch.  Plot the graph of his change in height per year.

For this we know that the slope of the line is 1, and that in the 8th year he was 70 inches tall:

y=x+b -> 70=8+b -> b=62

Therefore, the equation of the line is y=x+62

To plot this line we can start at the y-intercept (0,62), and then move up one unit and over one unit as we draw the line.

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