30 points reward, i literally have no clue

The explanation for this is one of my favorite pieces of mathematical reasoning. First, let's thing about distance; what's the shortest distance between two points? A straight line. If we just drew a straight line between A and B, though, we'd be missing a crucial element of the original problem: we also need to pass through a point on the line (the "river"). Here's where the mathemagic comes in.

If we take the point B and reflect it over the line, creating the point B' (see picture 1), we can draw a line straight from A to B' that passes through a point on the line. Notice the symmetry here; the distance from the intersection point to B' is the same as its distance to B. So, if we reflect that segment back up, we'll have a path to B, and because it came from of the line segment AB', we know that it's the shortest possible distance that includes a point on the line.

If we apply this same process to our picture, we see that the line segment AB' crosses the line at the point (1, 1)

yes because there is exactly one y value for every x value

for function there can't be more than one value for every x value