(-4,8)(6,13)
slope(m) = (13 - 8) / (6 - (-4) = 5 / (6 + 4) = 5/10 = 1/2
y = mx + b
slope(m) = 1/2
use either of ur points (6,13)...x = 6 and y = 13
now sub and find b, the y int
13 = 1/2(6) + b
13 = 3 + b
13 - 3 = b
10 = b
so ur equation is : y = 1/2x + 10 (slope intercept form)
or..
y = 1/2x + 10
-1/2x + y = 10...multiply by -2
x - 2y = -20 (standard form)