Answer:
Step-by-step explanation:
Recall that we say that d | a if there exists an integer k for which a = dk. So, let d = gcd(a,b) and let x, y be integers. Let t = ax+by.
We know that 
so there exists integers k,m such that a = kd and b = md. Then,
. Recall that since k, x, m, y are integers, then (kx+my) is also an integer. This proves that d | t.
Answer:
D
Step-by-step explanation:
D is more appropriate for distance formula because you are looking for the whole length between two points rather than the point in between the the two points such as in the other answers.
