Which of the coordinates listed below could represent a point found on the line 3x?

Well.. You seem to have forgotten to add the coordinates...

Anyway, the line is represented by the function f(x) = 3x .

Any point which follows the form (x,3x) will be on the line

for example (-3,-9) ; (-2,-6) ; (-1,-3) ; (0,0) ; (0.333333,1) ; (1, 3) ; (2,6) ; (3,9) ; and so on

Khalid and Sue's Height together is 126 Inches. The difference is 6 inches, so therefore you subtract 6 from the total getting you 120 Inches. You do this with all of the problems for example: The first one. Sue is 72 inches and Khalid is 54. Add them together and subtract them by 6 to get your final answer. Please DO NOT quote me on this lol. This is how I read the question. I think this is right but I am not absolutely 100% sure. Hope this helps.