Finding Slope and Y-Intercept

This Movie (Quicktime)
will show you how to find the slope and y-intercept given the equation of a line.

The following is the movie transcript.

Hi my name is Paul and my topic is Slope and the slope-intercept form of equations. I’m going to show you how to find the slope and y-intercept given the equation of a line and find the equation of a line given the slope and y-intercept.

When an equation is written in the form y = mx + b, the slope of the line and y-intercept of a line can be determined by inspection.  Here we'll find the slope and y-intercept given the equation of a line y = mx + b where m is the slope and b is the y coordinate of the y-intercept.

For example, we’ll find the slope and y-intercept of the lines with the following equations. In this equation y equals three-fifths x plus 2, the slope is three over five and the y-intercept is 2 or the ordered pair (0,2). Another example, y equals 3x minus 4, the slope equals 3 or 3 over 1 and the y-intercept equals negative 4 or the ordered pair (0, negative 4).

In this last example, which is written in standard form, we have 2x minus 5y equals 10. We’ll solve for y, negative 5y equals negative 2x plus 10. Divide by negative 5 on both sides of the equation and you end with y equals two-fifths x minus 2. Your slope will equal two-fifths and your y-intercept will equal negative 2 or the ordered pair (0,negative 2).

For the second part of my topic, we want to find the equation of a line given the slope and y-intercept.
First, use the slope-intercept form of an equation of a straight line y = mx + b.
Second,you want to substitute known values for mx+b.
Finally, you write the equation in standard form or slope-intercept form.

For example, write the equation for a line with a slope of negative 3 and a y-intercept of 5. We know the slope is negative 3 and the y-intercept is 5. So substitute the known values in the equation and you come up with y equals negative 3x + 5.

This is my podcast on slope and the slope-intercept form of equations.

End Movie Transcript

This podcast was created by Paul in Mrs. Linebarger's Algebra class at Southwest Tennessee Community College.  www.southwest.tn.edu.

http://ww4.southwest.tn.edu/podcast/llinebarger/Paul.m4v

Posted at 01:10PM Feb 09, 2007 by llinebarger in Intermediate Algebra  |