Let
P1 = (x1, y1) = (4, 7)
P2 = (x2, y2) = (2, 3)
The first thing to do in this case is to find the distance between two points by the following equation:
d (P1, P2) = root ((x2-x1) ^ 2 + (y2-y1) ^ 2)
d (P1, P2) = root ((2-4) ^ 2 + (3-7) ^ 2) = 4.47
answer
The houses are separated 4.47 units.