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

\( \frac{2}{5} \) x \( \frac{1}{9} \) = \( \frac{2 x 1}{5 x 9} \) = \( \frac{2}{45} \) = \(\frac{2}{45}\)

To simplify this fraction, first find the greatest common factor between them. The factors of 16 are [1, 2, 4, 8, 16] and the factors of 68 are [1, 2, 4, 17, 34, 68]. They share 3 factors [1, 2, 4] making 4 their greatest common factor (GCF).

Next, divide both numerator and denominator by the GCF:

\( \frac{16}{68} \) = \( \frac{\frac{16}{4}}{\frac{68}{4}} \) = \( \frac{4}{17} \)

To simplify a radical, factor out the perfect squares:

\( \sqrt{80} \)
\( \sqrt{16 \times 5} \)
\( \sqrt{4^2 \times 5} \)
4\( \sqrt{5} \)

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

2\( \sqrt{8} \) x 8\( \sqrt{7} \)
(2 x 8)\( \sqrt{8 \times 7} \)
16\( \sqrt{56} \)

Now we need to simplify the radical:

16\( \sqrt{56} \)
16\( \sqrt{14 \times 4} \)
16\( \sqrt{14 \times 2^2} \)
(16)(2)\( \sqrt{14} \)
32\( \sqrt{14} \)

The equation for this sequence is:

a_n = a_n-1 + 5

where n is the term's order in the sequence, a_n is the value of the term, and a_n-1 is the value of the term before a_n. This makes the next number:

a₆ = a₅ + 5
a₆ = 21 + 5
a₆ = 26