We need to find a digit such that the value of x is a whole number. To do that, we can add 694 and 10 times the digit to both sides of the equation, to isolate x:
3x - 694 - 10* = 3x - 694 - 10* + 694 + 10*
Simplifying the right side of the equation:
3x = 694 + 10*
And finally, dividing both sides by 3:
x = (694 + 10*) / 3
Since x needs to be a whole number, (694 + 10*) must be divisible by 3. So (694 + 10*) must be either 697, 707, 717, ..., 993.
The possibilities for x are:
x = (697 + 0) / 3 = 232
x = (707 + 10) / 3 = 236
x = (717 + 20) / 3 = 240
...
x = (993 + 90) / 3 = 331
So the possible values of x are 232, 236, 240, ..., 331