If \( x+\frac{2}{7} x=9 \), then \( x= \)

Step 1 ：\( x + \frac{2}{7}x = 9 \)

Step 2 ：\( x\left(1 + \frac{2}{7}\right) = 9 \)

Step 3 ：\( x = \frac{9}{\frac{9}{7}} \)

Step 4 ：\( x = \frac{63}{9} \)

Step 5 ：\( x = 7 \)