SOLUTION: I have to write the slope-intercept form of the equation of the line described: through (-4,1) perpendicular to y = 5. y = 5 is a 0 slope so I'm not sure where to go from her

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Question 271960: I have to write the slope-intercept form of the equation of the line described:
through (-4,1) perpendicular to y = 5.
y = 5 is a 0 slope so I'm not sure where to go from her. Can you help me through this please?
Found 2 solutions by stanbon, Edwin McCravy:
Answer by stanbon(48545) About Me  (Show Source):
You can put this solution on YOUR website!
I have to write the slope-intercept form of the equation of the line described:
through (-4,1) perpendicular to y = 5.
y = 5 is a 0 slope so I'm not sure where to go from her.
--------------------------------
Right you are.
Draw the line y=5.
Plot the point (-4,1)
Do this so you can see what the problem requires.
----
If the line if perpendicular to y = 5 it must be a vertical line.
And that vertical line must pass thru (-4,1).
---
So draw a vertical line that passes thru (-4,1)
===============================
Now you have to notice that vertical line passes
thru all the points where x = -4.
THAT equation is the answer to your problem.
=================================================
Cheers,
Stan H.

Answer by Edwin McCravy(6936) About Me  (Show Source):
You can put this solution on YOUR website!
I have to write the slope-intercept form equation of the line described:
Y = 5 is a zero slope so I don't know where to go from here. Can you guide me through this?
Thanks
through (-4,1) perpendicular to y = 5.

This is a vertical line, which is the only case where 
there is no slope-intercept form.  However there is an
equation for it.

Let's begin by drawing the line whose equation is y = 5.
I'll draw it green.  I'll also plot the point (-4,1)

drawing%28400%2C400%2C-10%2C10%2C-10%2C10%2C+graph%28400%2C400%2C-10%2C10%2C-10%2C10%29%2C%0D%0Agreen%28line%28-11%2C5%2C11%2C5%29%29%0D%0Aline%28-4%2B.1%2C1%2C-4-.1%2C1%29%2C+line%28-4%2C1%2B.1%2C-4%2C1-.1%29%2C+line%28-4%2B.1%2C1%2B.1%2C-4-.1%2C1-.1%29%2C+line%28-4%2B.1%2C1-.1%2C-4-.1%2C1%2B.1%29%2Clocate%28-3.7%2C1.4%2C%27%28-4%2C1%29%27%29+%29



 )}}}
 

Now we'll draw a blue line through (-4,1) which is perpendicular 
to the green line  

drawing%28400%2C400%2C-10%2C10%2C-10%2C10%2C+graph%28400%2C400%2C-10%2C10%2C-10%2C10%29%2C%0D%0Agreen%28line%28-11%2C5%2C11%2C5%29%29%2C+blue%28line%28-4%2C11%2C-4%2C-11%29%29%2C%0D%0Aline%28-4%2B.1%2C1%2C-4-.1%2C1%29%2C+line%28-4%2C1%2B.1%2C-4%2C1-.1%29%2C+line%28-4%2B.1%2C1%2B.1%2C-4-.1%2C1-.1%29%2C+line%28-4%2B.1%2C1-.1%2C-4-.1%2C1%2B.1%29%2C%0D%0Alocate%28-4%2B.3%2C1.4%2C%27%28-4%2C1%29%27%29%0D%0A%0D%0A+%29

The way to determine its equation is to look at several points
on that blue vertical line and to observe what one thing is true about
all of them:

Lets look at some points on that blue vertical line:

drawing%28400%2C400%2C-10%2C10%2C-10%2C10%2C+graph%28400%2C400%2C-10%2C10%2C-10%2C10%29%2C%0D%0Agreen%28line%28-11%2C5%2C11%2C5%29%29%2C+blue%28line%28-4%2C11%2C-4%2C-11%29%29%2C%0D%0Aline%28-4%2B.1%2C1%2C-4-.1%2C1%29%2C+line%28-4%2C1%2B.1%2C-4%2C1-.1%29%2C+line%28-4%2B.1%2C1%2B.1%2C-4-.1%2C1-.1%29%2C+line%28-4%2B.1%2C1-.1%2C-4-.1%2C1%2B.1%29%2C%0D%0Alocate%28-4%2B.3%2C1.4%2C%27%28-4%2C1%29%27%29%2C%0D%0A%0D%0Aline%28-4%2B.1%2C3%2C-4-.1%2C3%29%2C+line%28-4%2C3%2B.1%2C-4%2C3-.1%29%2C+line%28-4%2B.1%2C3%2B.1%2C-4-.1%2C3-.1%29%2C+line%28-4%2B.1%2C3-.1%2C-4-.1%2C3%2B.1%29%2C%0D%0Alocate%28-4%2B.3%2C3%2B.4%2C%27%28-4%2C3%29%27%29%2C%0D%0A%0D%0Aline%28-4%2B.1%2C5%2C-4-.1%2C5%29%2C+line%28-4%2C5%2B.1%2C-4%2C5-.1%29%2C+line%28-4%2B.1%2C5%2B.1%2C-4-.1%2C5-.1%29%2C+line%28-4%2B.1%2C5-.1%2C-4-.1%2C5%2B.1%29%2C%0D%0Alocate%28-4%2B.3%2C5%2B.4%2C%27%28-4%2C5%29%27%29%2C%0D%0A%0D%0A%0D%0Aline%28-4%2B.1%2C-3%2C-4-.1%2C-3%29%2C+line%28-4%2C-3%2B.1%2C-4%2C-3-.1%29%2C+line%28-4%2B.1%2C-3%2B.1%2C-4-.1%2C-3-.1%29%2C+line%28-4%2B.1%2C-3-.1%2C-4-.1%2C-3%2B.1%29%2C%0D%0Alocate%28-4%2B.3%2C-3%2B.4%2C%27%28-4%2C-3%29%27%29%2C%0D%0A%0D%0Aline%28-4%2B.1%2C7%2C-4-.1%2C7%29%2C+line%28-4%2C7%2B.1%2C-4%2C7-.1%29%2C+line%28-4%2B.1%2C7%2B.1%2C-4-.1%2C7-.1%29%2C+line%28-4%2B.1%2C7-.1%2C-4-.1%2C7%2B.1%29%2C%0D%0Alocate%28-4%2B.3%2C7%2B.4%2C%27%28-4%2C1%29%27%29%2C%0D%0A%0D%0Aline%28-4%2B.1%2C-8%2C-4-.1%2C-8%29%2C+line%28-4%2C-8%2B.1%2C-4%2C-8-.1%29%2C+line%28-4%2B.1%2C-8%2B.1%2C-4-.1%2C-8-.1%29%2C+line%28-4%2B.1%2C-8-.1%2C-4-.1%2C-8%2B.1%29%2C%0D%0Alocate%28-4%2B.3%2C-8%2B.4%2C%27%28-4%2C-8%29%27%29%2C%0D%0A%0D%0A%0D%0Aline%28-4%2B.1%2C-5%2C-4-.1%2C-5%29%2C+line%28-4%2C-5%2B.1%2C-4%2C-5-.1%29%2C+line%28-4%2B.1%2C-5%2B.1%2C-4-.1%2C-5-.1%29%2C+line%28-4%2B.1%2C-5-.1%2C-4-.1%2C-5%2B.1%29%2C%0D%0Alocate%28-4%2B.3%2C-5%2B.4%2C%27%28-4%2C-5%29%27%29++%29

Notice what all those points

(-4,5), (-4,3), (-4,1), (-4,-3), (-4,-5), (-4,-8)

have in common.  They all have their x-coordinates

equal to -4.  So all we do is write that the x
value on every point on that line is -4, and to do that
we simply write the simple equation

x = -4 

That equation is only true for points on that line,
so that is the equation of the blue vertical line.  There
is no slope-intecept for it because there is no "m",
because vertical lines do not have a slope.  There is
also no "b" because vertical lines have no y-intercept.

So the only thing we can do is write the simple equation
which describes every point on that blue vertical line, which
is x = -4.

Edwin