Answer :

The line x=15 is the line parallel to the axis OY.
So the paralel lines to the line x=15 are  parallel  to the axis OY, so their equations are  x=a,  where "a"  is a real number. 
Here you've got point (-1,5) so x-coordinate is x=-1, 
So equation this line  is x=-1
....
[tex]Look\ at\ the\ picture.\\\\x=-1\ is\ parallel\ to\ the\ x=15\ and\ contains\ the\ point\ (-1;\ 5)[/tex]
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