To divide fractions, invert the second fraction and then multiply:

\( \frac{4}{7} \) ÷ \( \frac{4}{6} \) = \( \frac{4}{7} \) x \( \frac{6}{4} \)

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

\( \frac{4}{7} \) x \( \frac{6}{4} \) = \( \frac{4 x 6}{7 x 4} \) = \( \frac{24}{28} \) = \(\frac{6}{7}\)

To add or subtract terms with exponents, both the base and the exponent must be the same. In this case they are so add the coefficients and retain the base and exponent:

-5c⁷ + 4c⁷
(-5 + 4)c⁷
-c⁷

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

5\( \sqrt{28} \) + 6\( \sqrt{7} \)
5\( \sqrt{4 \times 7} \) + 6\( \sqrt{7} \)
5\( \sqrt{2^2 \times 7} \) + 6\( \sqrt{7} \)
(5)(2)\( \sqrt{7} \) + 6\( \sqrt{7} \)
10\( \sqrt{7} \) + 6\( \sqrt{7} \)

Now that the radicands are identical, you can add them together:

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.

A prime number is an integer greater than 1 that has no factors other than 1 and itself. Examples of prime numbers include 2, 3, 5, 7, and 11.