You can put this solution on YOUR website!
If you can sketch the graph, then try to draw a vertical line through the graph in such a way that it crosses the graph two or more times. If a vertical line crosses the graph in TWO or more points, then the graph is NOT a function.
From the perspective of the equation, if you can write the equation in the form y =(________), with almost anything in the blank space, then it IS a function. However, if it comes out with a y = +-(_____) (that is a PLUS or MINUS), then it is NOT a function. If the equation has a y^2 or y^4 or y^ (even power). then generally, it is NOT a function.
R^2 at SCC