1. Well you know that Adam's age (a) is TWICE the amount of Bob's age, plus eight. So if Adam is a years old, you will need to multiply it by two and add eight

2. noooo friggen clue. I know it has to do with ratios but without a number I can't get it LOL

3. If five books cost D dollars, then you would find it easier to find out how much EACH book cost, so you would need to divide d / 5. Then after you find that price, you can multiply it by seven.

I hope I helped without giving too much away... Because GOSH its been years since I've taken any math classes LOL