To multiply terms with radicals, multiply the coefficients and radicands separately:

5\( \sqrt{4} \) x 6\( \sqrt{4} \)
(5 x 6)\( \sqrt{4 \times 4} \)
30\( \sqrt{16} \)

Now we need to simplify the radical:

30\( \sqrt{16} \)
30\( \sqrt{4^2} \)
(30)(4)
120

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

\( \frac{11 + 5 + 11 + 5}{4} \) = \( \frac{32}{4} \) = 8

There are 4 4-passenger taxis available so that's 4 x 4 = 16 total seats. There are 18 people needing transportation leaving 18 - 16 = 2 who will have to find other transportation.

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

5\( \sqrt{75} \) - 9\( \sqrt{3} \)
5\( \sqrt{25 \times 3} \) - 9\( \sqrt{3} \)
5\( \sqrt{5^2 \times 3} \) - 9\( \sqrt{3} \)
(5)(5)\( \sqrt{3} \) - 9\( \sqrt{3} \)
25\( \sqrt{3} \) - 9\( \sqrt{3} \)

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

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:

-1z² - 3z²
(-1 - 3)z²
-4z²