determine if this is a function?

y= x
show working method please

Graph the Eq and draw a vertical line

through it. The line will intersect the
graph at only one point. Therefore, the Eq is a function; because it passed the vertical line test.

If you graph an X-parabola and perform
the vertical line test, the line will
intersect the graph at 2 points. There-
fore, the X-parabola is not a function;
because it does not pass the vertical
line test.