3/7+х=3 4/7

To solve the equation \( \frac{3}{7} + x = 3 \frac{4}{7} \), follow these steps:

1. Convert \( 3 \frac{4}{7} \) into an improper fraction: \[ 3 \frac{4}{7} = 3 \times 7 + 4 = 21 + 4 = \frac{25}{7} \]

2. Now rewrite the equation: \[ \frac{3}{7} + x = \frac{25}{7} \]

3. Subtract \( \frac{3}{7} \) from both sides: \[ x = \frac{25}{7} - \frac{3}{7} \]

4. Perform the subtraction: \[ x = \frac{25 - 3}{7} = \frac{22}{7} \]

Thus, the solution is: \[ x = \frac{22}{7} \]

If you want to convert it back to a mixed number: \[ x = 3 \frac{1}{7} \]

So \( x = 3 \frac{1}{7} \) or \( \frac{22}{7} \).