Posted by Mathsnewbie on .
determine if this is a function?
y= x
show working method please

Maths 
Henry,
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 Xparabola and perform
the vertical line test, the line will
intersect the graph at 2 points. There
fore, the Xparabola is not a function;
because it does not pass the vertical
line test.