Write and equation for (-1,2) and (0,0)

Since the slope is -2 because
x1: -1 x2: 0
y1: 2  y2: 0
y2-y1/x2-x1 = slope (0-2/0+1= -2/1 = -2)

You would havr to change it into point slope form so it would look like this
Y-2 = -2(x+1)
 y-2 = -2x -2
   +2          +2
y = -2x + 0
Hope this helps:)