Hey there! :D
First, find the slope:
m= (y2-y1)/(x2-x1) (-4,2) and (-6,0)
m= (0-2)/(-6-(-4)
m= -2/(-6+4)
m=-2/-2
m=1
Now, plug that into point slope.
y-y1= m(x-x1)
y-2= 1(x-(-4)
y-2=1(x+4)
y-2=x+4
Add two to both sides.
y=x+6
The y-intercept= 6
I hope this helps!
~kaikers