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

\( \frac{4}{9} \) x \( \frac{2}{8} \) = \( \frac{4 x 2}{9 x 8} \) = \( \frac{8}{72} \) = \(\frac{1}{9}\)

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

\( \frac{15\sqrt{28}}{5\sqrt{7}} \)
\( \frac{15}{5} \) \( \sqrt{\frac{28}{7}} \)
3 \( \sqrt{4} \)

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

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

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

The amount of flour you need is (3\(\frac{1}{2}\) - 1\(\frac{1}{8}\)) cups. Rewrite the quantities so they share a common denominator and subtract:

(\( \frac{28}{8} \) - \( \frac{9}{8} \)) cups
\( \frac{19}{8} \) cups
2\(\frac{3}{8}\) cups

To fill a 8 gallon tank exactly halfway you'll need 4 gallons of fuel. Each fuel can holds 2 gallons so:

cans = \( \frac{4 \text{ gallons}}{2 \text{ gallons}} \) = 2