In the story "A White Heron" how would you describe Sylvia?

Sylvia, the protagonist of the story, is a 9-year-old girl living on a farm in the Maine woodlands with her grandmother, Mrs. Tilley.  Jewett describes Sylvia as a curious, observant, and shy young girl with a “pale face and shining gray eyes” that easily convey if she's feeling excited, scared, or troubled.

Explanation:

substitute y = 2x - 4 to x + 2y = 12:

x + 2(2x - 4) = 12     use distributive property

x + (2)(2x) + () = 12

x + 4x - 8 = 12     add 8 to both sides

5x = 20     divide both sides by 5

x = 4

put the value of x to the first equation:

y = 2(4) - 4

y = 8 - 4

y = 4