1) the vertical line test is the best way to insure whether or not a graph is a function. All the other graphs pasS the vertical line test but graph d does not, hence graph d is not a function.
2) to determine whether the table is a function or not you need to look at the "x" values. If there is a repeated number in the x values, the table does not represent a function. Table c is the only one that represents a function.
3) coordinate points b are the only ones without a repetition of x coordinate points. Hope this helps!
