tolong dijawab beserta caranya

y-y1/y2-y1 = x-x1/x2-x1
y-2/8-2 = x-2/4-2
y-2/6 = x-2/2
2y-4 = 6x-12
2y-4-6x+12 = 0
2y-6x+8 = 0
y-3x+4 = 0
y = 3x-4 -> gradien = 3

Yg gradien 3 jwbnnya yg A karena -(-3)/1 = 3