To simplify the expression \(\frac{3}{7}x + \frac{2}{7}x\), you can combine the like terms because they share a common denominator:
\[ \frac{3}{7}x + \frac{2}{7}x = \left(\frac{3+2}{7}\right)x = \frac{5}{7}x \]
Thus, the simplified expression is:
\[ \frac{5}{7}x \]