Algebra I
posted by A .
Hi, I would like someone to explain to me the process to get to the answer of these questions. (The answers are in the back of the book, but I don't understand how to get them myself):
QUESTION ONE
Warren has 40 coins (all nickels, dimes, and quarters) worth $4.05. He has 7 more nickels than dimes. How many quarters does Warren have?
QUESTION TWO
Find and simplify the sum of a^2(ab^3)^2, b^2(a^2b^2)^2
("^2" means "exponent of two" or "to the second power")
QUESTION THREE
Find and simplify the sum of
a(ab^2)^3 + (2a^2b^3)^2
QUESTION FOUR
Find and simplify the product of
a(ab^2)^3 x (2a^2b^3)^2
QUESTION FIVE
Show that 16^x times (4^x)^2 = (2^x)^8
I would really, really appreciate any help for any of the questions. I am trying so hard but I just don't get it!

1. Are you sure that is all the data you have? I can't solve without some relationship with quarters.
N = D + 7
25Q + 10D + 5N = 405
25Q + 10D + 5(D+7) = 405
2. (ab^3)^2 = a^2(b^6), assuming that only the b term is cubed. Power to a power is simplified by multiplying.
That should help you with the other problems too.