Answer: y=-1/3x+5
Step-by-step explanation: I presume they want this in the y=mx+b format where m is the slope (change in y/change in x) of the line and b is the y-intercept (what y is when x is equal to 0). To answer this you need to choose any 2 points on this graph. For simplicity's sake, I'm going to choose (0,5) and (9,2). What's good about choosing (0,5) is that we now know the y-intercept is 5. Now, to find slope, subtract the y coordinate 2 from the y coordinate 5. You now know that the change in y is 3. Then, subtract the x coordinate 9 from the x coordinate 0. You now know that the change in y is -9. Finally, divide 3 (change in y) by -9 (change in x) and you should get -3/9 which can be simplified into -1/3. So now that you have your y-intercept and your slope, all that's left to do in plug it into the format. So your answer should be y=-1/3x+5. Hope this helps you!
