slope intercept is y=mx+b
m=slope
slope if found by
m=(y1-y2)/(x1-x2)
(x,y)
(-1,-2) and
(1,2)
x1=-1
y1=-2
x2=1
y2=2
m=(-1-1)/(-2-2)
m=-2/-4
m=1/2
y=1/2x+b
solve fo by subsituting one x value
(1,2)
x=1
y=2
2=1/2(1)+b
2=1/2+b
subtract 1/2
3/2=b
equation is
y=1/2x+3/2
