Write an equation in the form y = mx + b for the line which passes through (6, 5) and
(-8, -23).
The slope of the line is (5+23)/(6+8) = 2
So, using the point-slope form of a line,
y-5 = 2(x-6)
y-5 = 2x-12
y = 2x-7
Or, you could go through the hassle of solving
6a+b = 5
-8a+b = -23
subtract to get
14a = 28
a=2
so b = -7