## Monday, February 28, 2011

### Graphing Linear Inequalities

To understand these videos (some go pretty fast), you must fully understand how to solve and graph linear equalities.  You must also know how to solve linear inequalities

You must be familiar with slope-intercept form (y = mx + b), and understand which numbers in the equation are m and b, and how to graph them.  Mark b on the graph, then graph the slope (m) from that point.
Inequalities are very similar, with only a few differences:
• It's not a line of solutions as in a linear equation; it is a solid or dashed boundary line that shows on which side all the solutions are.
• Shade above or below the boundary line, showing on which side all the solutions are.
• Change the direction of the inequality (>, <) if you divide by a negative number.
►These differences are explained in the fourth video.  It is fast, and it is good to pause the video to read the text on the board.
►Check your work by using (0,0) as a test point.  This will help you know if your answer is correct, and if you forgot to change the direction of the inequality.
These videos cover the same topic, but go about solving in slightly different ways.  I watched all of them, and gleaned a little more from each one.

(1) from YourTeacher.com - graphing using a table

(2) boundary line

(3) graphing using slope-intercept form, y = mx + b

(4) graphing using slope-intercept form.  He is fast, so pause and read the text on the board.

(5) graphing using slope-intercept form