What is the value of x? x 3 = 9

Assuming you mean 3 · x = 9, you can divide each side by 3 to get answer of x = 3.

If you mean x - 3 = 9. You can add 3 to each side and get an answer of x = 12.

If you mean x + 3 = 9. You can minus 3 to each side and get an answer of x = 6.

3 is the correct answer