Identifying Polynomial and Power Functions HELP!

I am so stuck on these problems and I need someone to explain to me how to do this. =\ Help will be greatly appreciated! =D

State whether the function is a POWER FUNCTION, a POLYNOMIAL FUNCTION, BOTH or NEITHER. Write the function in standard form (if it is either a polynomial or power function). For power functions, give the constant of variation and power. For polynomial functions, give the degree and leading term.

1. f(x) = 3(ex)^3

2. E(m) = mc^2

3. g(x) = k(2n)^5 - 2x^3 + 5x^4

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I am stuck =[ please help!

I will really appreciate it if you explain how you got the answers, if it isn't too much to ask. Thank you again!