a LINEar function has well, the graph of a straight line, so this isn't that.
is it a relation? well, yes, because the y-value correlates with the x-value, so one depends or relates to the other.
is it a non-linear function? well, a function has to pass the <u>vertical line test</u>, meaning if we draw vertical lines they must touch the graph only once on their way down.... and in this case it seems they do, so it is non-linear clearly, and it's also a function.