3x + y = 6. You're free to choose any x values you wish (at least, for this linear function). So, if you chose x = 0, y would be 6, and you'd enter 0 6 in the first row of the given table.
If you chose x = -2, then -6 + y = 6 and y would be 12. Enter -2 12 in the second row of the table.
You could also choose y values and calculate the related x-values.
