In order to find how many additional workers are needed to staff the extra crews you first need to calculate how many workers are on a crew. There are 9 workers at the company now and that's enough to staff 3 crews so there are \( \frac{9}{3} \) = 3 workers on a crew. 7 crews are needed for the busy season which, at 3 workers per crew, means that the roofing company will need 7 x 3 = 21 total workers to staff the crews during the busy season. The company already employs 9 workers so they need to add 21 - 9 = 12 new staff for the busy season.

To multiply fractions, multiply the numerators together and then multiply the denominators together:

\( \frac{4}{9} \) x \( \frac{4}{7} \) = \( \frac{4 x 4}{9 x 7} \) = \( \frac{16}{63} \) = \(\frac{16}{63}\)

A factorial has the form n! and is the product of the integer (n) and all the positive integers below it. For example, 5! = 5 x 4 x 3 x 2 x 1 = 120.

The distributive property for multiplication helps in solving expressions like a(b + c). It specifies that the result of multiplying one number by the sum or difference of two numbers can be obtained by multiplying each number individually and then totaling the results: a(b + c) = ab + ac. For example, 4(10-5) = (4 x 10) - (4 x 5) = 40 - 20 = 20.

To subtract these radicals together their radicands must be the same:

4\( \sqrt{80} \) - 4\( \sqrt{5} \)
4\( \sqrt{16 \times 5} \) - 4\( \sqrt{5} \)
4\( \sqrt{4^2 \times 5} \) - 4\( \sqrt{5} \)
(4)(4)\( \sqrt{5} \) - 4\( \sqrt{5} \)
16\( \sqrt{5} \) - 4\( \sqrt{5} \)

Now that the radicands are identical, you can subtract them: