Function/equation logarithmic

Hi I have a few I am stumped on in my wonderful challenge of Algebra.

First Problem is:

Use the compound interest formulas

A=P(1 + r over n)^nt and A=Pe^rt

Suppose that you have $14,000 to invest. Which investment yields the greater return over 10 years: 7% compounded monthly or 6.85% compounded continuously?

Second Problem:

find the domain of each logarithmic function.

F(x)=log(3-X)

Third Problem:

Solve each exponential equation by expressing each side as a power of the same base and then equating exponents.

9^x = 1 over 27