Question

A line passes through the points (p, a) and (p, –a) where p and a are real numbers. If p=0, what is the y-intercept? Explain your reasoning.

Answer 1

m = (y2 - y1) / (x2 - x1)

Using (–12, 1.5), and (8, −3.5)
m = (-3.5 - 1.5) / (8 - -12)
m = -5/ 20
m = -1/4

Slope intercept form is
y = mx + b

Using point (8, −3.5)
-3.5 = (-1/4)8 + b
-3.5 = -2 + b
b = -1.5

Therefor
y = (-1/4)x - 1.5