T389

c = -0.7 (slider from -5 to 5)
eq1: (c * x) + x - y = 0
eq2: ((6 * c) * x) - (2 * y) = 0
A = Point(eq1)
B = Point(eq2)
C = Intersect(eq2, eq1)
α = Angle(B, C, A)