Answer:
y = 0x + 2
Step-by-step explanation:
Find the slope.
Slope = <u> y2 - y1</u>
               x2 - x1
Plug in the points.
 
 Slope =    <u>2 - 2</u>         =   <u>0</u>
                 -7 - 8            -15
Pick a point to plug into the y = mx + b formula
I picked (8,2)
Now plug in the point and slope.
(Your teacher might prefer you to use 0/-17, but it can be simplified to 0, so I'll just use that.)
Equation: (2) = 0(8) + b
                  2  = 0 + b
                  2 = b  (b = 2)
Now put your slope and the y-intercept into the equation, and it will be:
y = 0x + 2
It's a bit hard to show on keyboard, so I hope you understand.