The initial value is the y-intercept, which is our letter b in the form y = mx + b.
1. Find slope.
m = (0 - 2)/(5 - 0)
m = -2/5
2. Plug one of the given points and the slope into the point-slope formula.
I will use (5, 0).
y - 0 = (-2/5)(x - 5)
y = (-2/5)(x) + 2
The initial value is 2.