To add these fractions, first find the lowest common multiple of their denominators. The first few multiples of 3 are [3, 6, 9, 12, 15, 18, 21, 24, 27, 30] and the first few multiples of 9 are [9, 18, 27, 36, 45, 54, 63, 72, 81, 90]. The first few multiples they share are [9, 18, 27, 36, 45] making 9 the smallest multiple 3 and 9 share.

Next, convert the fractions so each denominator equals the lowest common multiple:

\( \frac{6 x 3}{3 x 3} \) + \( \frac{2 x 1}{9 x 1} \)

\( \frac{18}{9} \) + \( \frac{2}{9} \)

Now, because the fractions share a common denominator, you can add them:

\( \frac{18 + 2}{9} \) = \( \frac{20}{9} \) = 2\(\frac{2}{9}\)

To take the square root of a fraction, break the fraction into two separate roots then calculate the square root of the numerator and denominator separately:

\( \sqrt{\frac{9}{64}} \)
\( \frac{\sqrt{9}}{\sqrt{64}} \)
\( \frac{\sqrt{3^2}}{\sqrt{8^2}} \)
\(\frac{3}{8}\)

To raise a term with an exponent to another exponent, retain the base and multiply the exponents:

To simplify a radical, factor out the perfect squares:

\( \sqrt{125} \)
\( \sqrt{25 \times 5} \)
\( \sqrt{5^2 \times 5} \)
5\( \sqrt{5} \)

By buying two shirts, Roger will save $39 x \( \frac{30}{100} \) = \( \frac{$39 x 30}{100} \) = \( \frac{$1170}{100} \) = $11.70 on the second shirt.

So, his total cost will be
$39.00 + ($39.00 - $11.70)
$39.00 + $27.30
$66.30