You give up too easily.

How?

I posted how to get the answer below at the original question.

OK but I replied...

As did I.

Well...I replied...again...

Maybe you do understand this for horizontal lines.

If you interchange x with y, vertical and horizontal lines are interchanged (you reflect everything in the line x = y)

If the question is:

"Write the equation of a horizontal line passing through the point (-4,8)",

then I think you understand that the equation is:

y = 8,

which you can write as:

y = 8 + 0 x

where the zero is the slope of the line.

If you interchage x with y the horizontal line becomes a vertical line and the equation ecomes:

x = 8