Answer: -20x+30 ?
Explanation: You can find the slope by using the RISE/RUN method. You find two points that don't result in a fraction/decimal. In this pic, it would be (10,10) and (0,30). From (10,10) you go up the y-axis by two points and go to the left of the x-axis 1 time to get to point (0,30) to get 20/1 or 20. 20 would be negative because the line goes from left to right going down. The y-intercept would be 30. So it would be -20x+30. Hope this helped!!!!