x = -3 is a vertical line at x = -3.
The domain is x = -3 because x can't be at any point on the x-axis other than -3.
the range is infinity because y can take on any value along the y-axis.
this is not a function because there are more than one value of y for a specific value of x.
it is therefore a relation.
the graph of x = -3 looks something like this:
it's a vertical line at x = -3.
a table of values for this graph would be something like this:
x y
-3 -1000
-3 -500
-3 0
-3 500
-3 1000
in other words, x can only be -3 and y can be any value along the y-axis.
there are an infinite number of possible values of y for that one value of x.
x can't take on any other value.
y can take on any value.
in interval notation, your domain would be x = [-3,-3].
that means that -3 is <= x which is <= -3.
that forces x to be equal to -3.
it can't be less than -3 and it can't be greater than -3 so it has to be -3.
in interval notation, your range would be y = (-infinity,infinity).
that means that y can be any value.