For t>0, log(t over t + 1) =

a. log(t) - log(t+1)

b. log(t) over log(t+1)

c. log(t+1)

d. log(1/2)

If logk(x) = -3 then x =

a. -1/k^3

b. -3k

c. 1 over k^3

d. 1 over 3k