40% of the water consumption is industrial use and 30% is personal use so (40% - 30%) = 10% more water is used for industrial purposes. 35,000 gallons are consumed daily so industry consumes \( \frac{10}{100} \) x 35,000 gallons = 3,500 gallons.

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

9\( \sqrt{8} \) - 4\( \sqrt{2} \)
9\( \sqrt{4 \times 2} \) - 4\( \sqrt{2} \)
9\( \sqrt{2^2 \times 2} \) - 4\( \sqrt{2} \)
(9)(2)\( \sqrt{2} \) - 4\( \sqrt{2} \)
18\( \sqrt{2} \) - 4\( \sqrt{2} \)

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

Monica scored 95% on the test meaning she earned 95% of the possible points on the test. There were 320 possible points on the test so she earned 320 x 0.95 = 304 points. Each question is worth 4 points so she got \( \frac{304}{4} \) = 76 questions right.

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

3\( \sqrt{9} \) x 8\( \sqrt{9} \)
(3 x 8)\( \sqrt{9 \times 9} \)
24\( \sqrt{81} \)

Now we need to simplify the radical:

24\( \sqrt{81} \)
24\( \sqrt{9 \times 9} \)
24\( \sqrt{9 \times 3^2} \)
(24)(3)\( \sqrt{9} \)
72\( \sqrt{9} \)

To simplify a radical, factor out the perfect squares:

\( \sqrt{45} \)
\( \sqrt{9 \times 5} \)
\( \sqrt{3^2 \times 5} \)
3\( \sqrt{5} \)