You're given a distance formula.

The derivative of distance is velocity, so for (a) derive the equation and find the sign of the velocity equation at those points.

For part b/c, just picture a 45-45-90 triangle, just for reference. Each leg of the triangle has a length of , but in this calculation x doesn't matter.

So if you draw a triangle which has a left endpoint connected to the origin, then the hypotenuse becomes a line with a slope 45 degrees with respect to the x axis.

So for (b) you just need to find where on x > 0 the slope of y = 1. Which should be easy assuming you have a basic understanding of these concepts.