(1) let "r" denote number of rabbits, "c" number of chickens
Set up the equations:

Answer: There are 575 rabbits and 425 chickens
(2) m - number of Mike's stamps, a - number of Andrew's stamps.
Set up equations:

Answer: Mike has 48 stamps. Andrew has 12 stamps.
Number of ways to select 3 books from 13 books for adoption is 286 .
<u>Step-by-step explanation:</u>
A Permutation is an ordered Combination. When the order does matter it is a Permutation. There are basically two types of permutation:
- Repetition is Allowed: such as the lock above. It could be "333".
- No Repetition: for example the first three people in a running race. You can't be first and second.
Formula is given by:
, where n is the number of things to choose from, and we choose r of them, no repetitions, order matters. Here , n=13 , r=3.
⇒ 
⇒ 
⇒ 
⇒ 
⇒ 
∴ Number of ways to select 3 books from 13 books for adoption is 286 .
1 and 3 they share a relationship of +2, 3 and 6 share x2, 5 and 8 share +3, 7 and 21 share x3
The expansion of a perfect square is

In words, the square of a sum of two terms is the sum of the squares of the two terms (
and
), plus twice the product of the two terms (
)
So, when determining if you have a perfect square trinomial, you should have two perfect squares. Note that they don't have to be the first and third term, since you can rearrange terms as you prefer.
<span>Equivalent ratios are ratios that name the same comparison. Meanwhile, equivalent fractions </span><span>are fractions that name the same amount or part. Equivalent ratios and equivalent fractions are similar in that the two quantities refer to ratios and fractions that ultimately have the same value but are expressed in a different way. For example, 48/64 is equivalent to 72/96, both have the value of 3/4. </span>