18. This question has three answer choices. Select all the answer choices that apply. The correct answer to a question of this type could consist of as few as one, or as many as all three of the answer choices.
If c and d are positive integers and m is the greatest common factor of c and d, then m must be the greatest common factor of c and which of the following integers?
1
c + d2
2 + d3
cd4
2d5
d2
Let’s let c = 4 and d = 6, so m = GCF(4, 6) = 2. Let’s analyze each choice.
A. c + d = 10, and GCF(4, 10) = 2, so A could be the answer.
B. 2 + d = 8, and GCF(4, 8) = 4, so B could not be the answer.
C. cd = 24, and GCF(4, 24) = 4, so C could not be the answer.
D. 2d = 12, and GCF(4, 12) = 4, so D could not be the answer.
E. d^2 = 36, and GCF(4, 36) = 4, so E could not be the answer.