Question 82003
How do I demonstrate an algebraic equation on a "number line"? For example, how do I show X<6 on a "number line"?
<pre><font size = 5><b>
First draw a number line like this:

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 -6 -5 -4 -3 -2 -1  0  1  2  3  4  5  6  7  8  9 10     

Since it's " < ", we put an OPEN circle at 6

--------------------------------------o------------
 -6 -5 -4 -3 -2 -1  0  1  2  3  4  5  6  7  8  9 10

(If it were " <u><</u> ", we'd put a closed circle)

Now since it's LESS THAN, we darken the number line
to the LEFT of 6 and put an arrowhead on the far left
end to show that it continues indefinitely to the
left.

<=====================================o------------
 -6 -5 -4 -3 -2 -1  0  1  2  3  4  5  6  7  8  9 10

That's the graph of x < 6.

Another example:

To draw the graph of x <u>></u> -3
put a closed circle at -3 like this:

-----------<font face = "webdings">=</font>---------------------------------------
 -6 -5 -4 -3 -2 -1  0  1  2  3  4  5  6  7  8  9 10 

It's a closed circle because the inequality
symbol is <u>></u>

Then since it's GREATER THAN, we darken the number line
to the RIGHT of -3 and put an arrowhead on the far right
end to show that it continues indefinitely to the
right.

-----------<font face = "webdings">=</font>=======================================>
 -6 -5 -4 -3 -2 -1  0  1  2  3  4  5  6  7  8  9 10

That's the graph of x <u>></u> -3

Edwin</pre>