First we calculate how many ways you can choose four books from a set of eight.
We use the formula n! / [r! * (n-r)!]
8! / [4! * 4!]
= 8*7*6*5 / 4*3*2*1 = 70 ways
Then we have to calculate how many permutations can be made from 4 objects which equals 4*3*2*1 = 24
So, the TOTAL number of ways = 70 * 24 = 1,680
Answer: 
Step-by-step explanation:
We can first take out the common factor of 4, as both 4x² and -32 are divisible by 4.

From here, we can assume that x²-8 is a difference of two squares even though 8 is not a perfect square.
<em>For review, a difference of two squares </em>
can be factored into
.

<span> (6y^2 + 4y + 5) – (3 – 7y + y^2)
= </span><span> 6y^2 + 4y + 5 – 3 + 7y - y^2
= 5</span>y^2 + 11y + 2
hope it helps
Answer:
18.05
Step-by-step explanation: