To find the y intercept, we first need to solve for the slope.
(y2-y1)/(x2-x1)
(2-(-1))/(-4-8)
(3)/(-12)
-1/4
Next, use the point slope equation to find the y intercept
y-y1=m(x-x1)
Either of the points given work
y-(-1)=-1/4(x-8)
y+1=-1/4x+2
y=-1/4x+1
So your answer is 1