Form a matrix of four by four to represent the information from four grade nine streams' mathematics contest results.

Rows correspond to the expectation categories: Exceeding, Meeting, Approaching, Below.
Columns correspond to the streams: North, South, East, West.

The matrix representing the information is $\boxed{\begin{pmatrix} 9 & 10 & 8 & 6 \\ 4 & 2 & 9 & 14 \\ 11 & 12 & 8 & 2 \\ 2 & 3 & 1 & 4 \end{pmatrix}}$.

28. Prepare a matrix of your choice of integers between -2 and 6 of order two by two.

The matrix must be of order $2 \times 2$, meaning it has 2 rows and 2 columns.
The elements must be integers between -2 and 6 (inclusive). This means the integers can be -2, -1, 0, 1, 2, 3, 4, 5, 6.

For example, we can choose 1, 0, 5, and -1.

A possible matrix is $\boxed{\begin{pmatrix} 1 & 0 \\ 5 & -1 \end{pmatrix}}$.
(Other valid answers are possible, as the choice is arbitrary within the given constraints.)

29. Evaluate:

The evaluated matrix is $\boxed{\begin{pmatrix} 5 & -5 \\ 12 & 8 \\ 12 & -6 \end{pmatrix}}$.

30. What is the order of

There are 2 rows in the matrix.

There are 3 columns in the matrix.

The order of the matrix is $\boxed{2 \times 3}$.

31. A girl is twice as old as a boy who is $x$ years old now. Their father is 25 years older than the girl. If the sum of their ages is 75, how old is the girl now?

Boy's age $= x$ years
Girl's age $= 2 \times x = 2x$ years
Father's age $= \text{Girl's age} + 25 = 2x + 25$ years

Sum of ages $= \text{Boy's age} + \text{Girl's age} + \text{Father's age}$

Subtract 25 from both sides:

Divide by 5:

Girl's age $= 2x = 2 \times 10 = 20$ years

The girl is $\boxed{20 \text{ years old}}$.