11) ((x+2/3) + 1/3(x+2/3)) * 1/3 =

Solution:

• Combine like terms inside the parentheses:
  Let y = (x + 2/3). The expression becomes:
  \( (y + \frac{1}{3}y) \cdot \frac{1}{3} \)
  \( (\frac{4}{3}y) \cdot \frac{1}{3} \)
• Substitute back y = (x + 2/3):
  \( \frac{4}{3}(x + \frac{2}{3}) \cdot \frac{1}{3} \)
• Distribute:
  \( \frac{4}{9}(x + \frac{2}{3}) \)
  \( \frac{4}{9}x + \frac{4}{9} \cdot \frac{2}{3} \)
  \( \frac{4}{9}x + \frac{8}{27} \)

Answer: 4/9x + 8/27