Its tough to answer if you don’t actually ask a question, based on what they tell you, they are probably trying to ask you something y=mx+b type equations. So went from 189 pounds to 162 pounds, how much weight did he lose?
Right! 27 pounds, good job!
Ok, and over how many weeks did that take place? Don’t know? Ok, well it started after week 3, and ended after week 12, so what does that tell you? Exactly, he lost 27 pounds over 9 weeks.
Ok, so how much is that each week? Yes, 27 divided by 3. Ok, now do the math, I'm not here to do the dirty work, I already graduated from college. Yes, 3 pounds per week.
Yes, you are right, that is pretty tough and probably unhealthy to lose that much weight in that short of a time and completely crazy to think this would follow the path of a line, but it’s not real life, it’s just a math problem.
Now can you figure out what he weighed before he joined the gym? Well if he weighed 189 pounds after week 3, how much did he lose in 3 weeks? Yes, 9 pounds, good thinking. So before that he weighed 189+9 or 198 pounds. Your linear equation could be written as:
Y = 198 – 3x where y is weight and x is number of weeks he has joined the gym. But if you want to make it y=mx+b form, write it as y = -3x+198.
Also if you see these two things written in (x,y) form you would have (3, 189) and (12,162) and you've probably learned a bunch of different things you can do with two points like get slope, find y-intercept and then maybe even find another point on the line from that information. (i.e. when did Mr. Suarez weigh 174 pounds?)