To find the slope, you divide the difference of the y-coordinates of 2 points on a line by the difference of the x-coordinates of those same 2 points .
The answer would be 46/219 or 0.21 or 21%. These all could be the possible answers, but written differently (just depends on how you want to write it). And it is because there are 46 non-social media users out of the whole entire total of 219 people, so you just divide 46 by 219 to get your answer.