since the equation doesn’t have a constant term following the slope then it goes through the origin (0,0)
so start from the origin and go down 2.5 and over to the right 1 and keep repeating that pattern
then to make the left end of the line, go 2.5 up and 1 left
this will result in a line going downwards at a slope of 2.5 (aka making a y = -2.5x line)