the first one is this right: [0] [0] , algebraically it means 0 units across and 0 units up...geometically it is basically a dot.
the second one: [3] [4], geometrically it is a line that is drawn from a point that can be resolved into 3 units across and 4 units up; algebraically it has a magnitude or value(length of the line) that is given by √a^2+b^2 which is in this case [\sqrt{3^2 +4^2}\] = 5
as a further note on geometry, imagine a straight line of length 5 units that is put at some angle on the (x,y) plane such that from its start to its endpoint is 3 units in the x direction but 4 units in the y direction
