Question

Which is a counterexample that disproves the conjecture?



If n is a positive integer, then 2^n – 1 is a prime number.



A.


n = 6


B.


n = 5


C.


n = 3


D.


n = 2

Answer 1

@goformit100

Answer 2

@SithsAndGiggles

Answer 3

Plug in each answer choice. If one of them gives you a number that is NOT prime...that's your counterexampler

Answer 4

\[2^n-1\]

Answer 5

i tried that, but two came out prime

Answer 6

either that or my calculator is broken

Answer 7

You're looking for the one that is NOT prime. That will prove the conjecture false. Only one answer is NOT prime.

Answer 8

let me try again

Answer 9

hint: 63/3 = 21 is not prime