Five logarithmic problems. Please help me!:(

Hi, guys. I missed school for a while and we're learning these stuff.
Plus, I'm totally lost. I need to check the answer but I didn't get the answer sheet :/
Just an answer would be fine, but explaination would be even more great.

Please help me! :(


1. If 2^5x-8 = 16^x, what is the value of x?

2. if log(sub10)x=5, what is the value of x?

3. What is the expression of log(sub5) 3x/2y?

4. What is the equation of log(sub3)243=x?

5. What are the solutions to the equation x^-2/3 = 4?

Im assuming it's 2^(5x - 8) = 16^x, not 2^(5x) - 8 = 16^x

2^(5x - 8) = 2^(4x)
5x - 8 = 4x
x = 8

log_10(x) = 5
10^5 = x
100,000 = x

log_5((3x)/(2y))
= log_5(3x) - log_5(2y)

log_3(243) = x
3^x = 243
3^x = 3^5
x = 5

x^(-2/3) = 4
x = 4^(-3/2)
x = 2^(-3)
x = 1/8

Hope this helps :D