binomial distribution dice and coins

Hey, so I have 2 questions for now that I really need some help on. The first is...

1. A person rolls a pair of fair dice. What is the probability that this person will roll no 7's on three rolls

2. If five coins are tossed simultaneously, what is the probability of obtaining exactly two tails? Is the result the same if one coin is tossed five times?

~If it is at all possible to give really detailed step by step guide to these questions it would be really helpful.

Thanks

~G