To subtract 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:

\( \frac{3 x 3}{3 x 3} \) - \( \frac{7 x 1}{9 x 1} \)

\( \frac{9}{9} \) - \( \frac{7}{9} \)

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

\( \frac{9 - 7}{9} \) = \( \frac{2}{9} \) = \(\frac{2}{9}\)

The greatest common factor (GCF) is the greatest factor that divides two integers.

First, solve for \( \left|a - 6\right| \):

\( \left|a - 6\right| \) + 2 = 1
\( \left|a - 6\right| \) = 1 - 2
\( \left|a - 6\right| \) = -1

The value inside the absolute value brackets can be either positive or negative so (a - 6) must equal - 1 or --1 for \( \left|a - 6\right| \) to equal -1:

So, a = 7 or a = 5.

The ratio of football cards to baseball cards is 3:2 and the ratio of baseball cards to basketball cards is 3:1. To solve this problem, we need the baseball card side of each ratio to be equal so we need to rewrite the ratios in terms of a common number of baseball cards. (Think of this like finding the common denominator when adding fractions.) The ratio of football to baseball cards can also be written as 9:6 and the ratio of baseball cards to basketball cards as 6:2. So, the ratio of football cards to basketball cards is football:baseball, baseball:basketball or 9:6, 6:2 which reduces to 9:2.

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.