Answer:
y=-x+9
Step-by-step explanation:
m=(y2-y1)/(x2-x1)
m=(9-0)/((0-9))
m=9/(0-9)
m=9/-9
m=-1
y=mx+c
y=-1*x+c
y=-x+c
plug in (9,0) into the equation
0=-1*9+c
0=-9+c
-c=-9
c=9
y=-x+9
you wrote it correctly too, but I think the problem is that it only takes -x not -1x
