<PRE><B>Question 702208</B>
&lt;br&gt;&lt;font face=&quot;Tahoma&quot;&gt;Horizontal and vertical lines are fairly straightforward.&lt;br&gt;

Horizontal lines are always written as {{{y=c}}} where c is a constant and the slope is zero.&lt;br&gt;

Vertical lines are always written as {{{x=c}}} where c is a constant and the slope is undefined.&lt;br&gt;

We are given the point (-5,-8)&lt;br&gt;

If we want the horizontal line at that point, we use the y value of -8:&lt;br&gt;

{{{y=-8}}} (will be the RED line) and this is a FUNCTION&lt;br&gt;

If we want the vertical line at that point, we use the x value of -5:&lt;br&gt;

{{{x=-5}}} (will be the GREEN line) and this is NOT a function&lt;br&gt;

{{{graph( 600, 600, -10, 10, -10, 10, -8, 100x+500 )}}}&lt;br&gt;

I hope this helps!  Keep practicing!  :)&lt;br&gt;

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