Gimana caranya ya ? Jelasin dong.. mksh

garis a melalui titik (-1,0) dan (0,2)
m = Y2 - Y1/ X2 - X1 = 2 - 0/0 + 1 = -2

m1 = -2 ; m2 = 1/2
garis b melalui titik (-1,0)
y - y1 = m (x - x1)
y - 0 = 1/2 (x + 1)
2y - 0 = x + 1
2y - x - 1 = 0