(2.01 lc)
is the following relation a function?
{(3,-2), (1, 2), (-1,-4), (-1, 2)}
o yes
o no

Why not? Because of the two points (-1,-4) and (-1,2)

The x values are repeating here. The input x = -1 leads to more than one output (y = -4 and y = 2 at the same time). A function is where all the inputs lead to only one output.

Visually if you plotted all four points, you will see it is possible to draw a vertical line through two of the points, those two points I mentioned earlier. This tells the reader that the relation fails the vertical line test and it shows it is not a function.