Find the Equation of a Line with Undefined Slope Passing Through (-1,4)

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Question:

Determine the equation the line passing through (-1,4) with undefined(infinite) slope.

I put "y=-1"

This was because if it was constant there would be a undefined slope?

Altough, it was obviously wrong.

Help please?

[Wrong section if possible get moved to homework]
 
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If you draw this line on a coordinate system you will get a vertical line passing through all y values when x=-1.

So x=-1 regardless of the y value, therefore the equation is x=-1

Let's generalize:

The equation of a vertical line passing through (a,b) will be x=a

You should also note that a vertical line does not represent a function because a function must match no more than one y value for any given x value. A vertical line matches infinite y values for one x value so it is not a function.
 
I noticed i did a simple mistake of accidently thinking of y=-1, and x=-1, for some reason was thinking on the wrong axis.

Thanks for the help