the x and y values in the table represent ordered pairs on the line.
let's say your table is the table below for the sake of my response.
x | y
1 | 4
3 | 12
think of both of these as ordered pairs, like (1,4) and (3,12).
after that, you'd graph both ordered pairs on your graph, and find the slope by putting your points into y2-y1/x2-x1 or just drawing a line between both points.
if i didn't understand your question properly, I apologize. If I did, you're welcome.