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

8\( \sqrt{27} \) + 8\( \sqrt{3} \)
8\( \sqrt{9 \times 3} \) + 8\( \sqrt{3} \)
8\( \sqrt{3^2 \times 3} \) + 8\( \sqrt{3} \)
(8)(3)\( \sqrt{3} \) + 8\( \sqrt{3} \)
24\( \sqrt{3} \) + 8\( \sqrt{3} \)

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

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

-9b² - 3b²
(-9 - 3)b²
-12b²

To find the average of these 4 numbers add them together then divide by 4:

\( \frac{18 + 12 + 16 + 14}{4} \) = \( \frac{60}{4} \) = 15

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

\( \frac{4}{8} \) x \( \frac{2}{7} \) = \( \frac{4 x 2}{8 x 7} \) = \( \frac{8}{56} \) = \(\frac{1}{7}\)

The factors of a number are all positive integers that divide evenly into the number. The factors of 20 are 1, 2, 4, 5, 10, 20.