I need help finding the answers to these, I did some of them but are unsure of the answer.

-Use the limit laws to find the limit if it exists:

1. lim x=> 0- square root of -x

i got 0 for this one, but i'm not sure

2. lim x=> 8 absolute value of (x-8)/x-8

i'm not entirely sure on this one

3. lim x=> 0 (1-2x)^3/x

i got zero on this one

4. lim x=> infinity 3e^3x+2e^x-1/e^3x-e^2x+5

no idea on this one

Any help would be a big help, thanks