MHB Can k be equal to 4 in the equation k + 2 = 3^(n)?

[mathdad]

If n is a positive integer and k + 2 = 3^(n), which of the following could NOT be a value of k?

A. 1
B. 4
C. 7
D. 25
E. 79

I say the answer is B or 4.

When k = 4, k + 2 becomes 6.
However, there is no power we can raised 3 to that will yield 6.

Is my reasoning correct?

 

[topsquark]

If n is a positive integer and k + 2 = 3^(n), which of the following could NOT be a value of k?

A. 1
B. 4
C. 7
D. 25
E. 79

I say the answer is B or 4.

When k = 4, k + 2 becomes 6.
However, there is no power we can raised 3 to that will yield 6.

Is my reasoning correct?

Looks good to me!

-Dan

 

[Wilmer]

Or since 3^(n) is odd, then k can't be 4.