Simplify the expression: (17)/(34) x (6)/(12) x (12)/(8)

First, simplify $\frac{17}{34}$ by dividing both numerator and denominator by 17:

$$\frac{\cancel{17}^1}{\cancel{34}_2}$$

Next, simplify $\frac{6}{12}$ by dividing both numerator and denominator by 6:

$$\frac{\cancel{6}^1}{\cancel{12}_2}$$

Then, simplify $\frac{12}{8}$ by dividing both numerator and denominator by 4:

$$\frac{\cancel{12}^3}{\cancel{8}_2}$$

$$\frac{1 \times 1 \times 3}{2 \times 2 \times 2} = \frac{3}{8}$$

The final answer is $\frac{3}{8}$.