Let r be a relation, x a set of attributes of r, and a an attribute of r. (also, denoted by x the result of adding a to x.) define the support of x, written #x, as the number of distinct tuples in r|x (r restricted to, or projected onto, the attributes of x). prove that if x-> a, then #x=#xa. (8 points)

step-by-step explanation:

the furthest the dog can be is 508 meters away from the house, and the closest he can be is 492 meters away from the house.

step-by-step explanation:

rectangles are made up of 4 right angles, which means that a side and a base meet perpendicular to one another.   their slopes then have to reflect perpendicular slopes.   perpendicular slopes are opposite reciprocals of one another.   for example, if the slope of one line is +2/3, then the perpendicular slope to that would be -3/2.   so we look for that combination in our choices.

all of them satisfy that condition (so what's the question, i guess? )