A factorial is the product of an integer and all the positive integers below it. To solve a fraction featuring factorials, expand the factorials and cancel out like numbers:

\( \frac{2!}{6!} \)
\( \frac{2 \times 1}{6 \times 5 \times 4 \times 3 \times 2 \times 1} \)
\( \frac{1}{6 \times 5 \times 4 \times 3} \)
\( \frac{1}{360} \)

To simplify this fraction, first find the greatest common factor between them. The factors of 28 are [1, 2, 4, 7, 14, 28] and the factors of 64 are [1, 2, 4, 8, 16, 32, 64]. They share 3 factors [1, 2, 4] making 4 their greatest common factor (GCF).

Next, divide both numerator and denominator by the GCF:

\( \frac{28}{64} \) = \( \frac{\frac{28}{4}}{\frac{64}{4}} \) = \( \frac{7}{16} \)

The factors of a number are all positive integers that divide evenly into the number. The factors of 24 are 1, 2, 3, 4, 6, 8, 12, 24.

By buying two shirts, Ezra will save $50 x \( \frac{10}{100} \) = \( \frac{$50 x 10}{100} \) = \( \frac{$500}{100} \) = $5.00 on the second shirt.

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

7\( \sqrt{4} \) x 2\( \sqrt{3} \)
(7 x 2)\( \sqrt{4 \times 3} \)
14\( \sqrt{12} \)

Now we need to simplify the radical:

14\( \sqrt{12} \)
14\( \sqrt{3 \times 4} \)
14\( \sqrt{3 \times 2^2} \)
(14)(2)\( \sqrt{3} \)
28\( \sqrt{3} \)