tolong kerjakan no 3,5,6

no 3
.A.
vektor AB
= B-A = (-2,1,2)-(3,4,5)
=(-5,-3,-3)
Vektor AC
=C-A = (8,-5,1)-(3,4,5)
=(5,-9,-4)

No 4
z = q. p / |p|
-⅔=(x,-3,-2)(-2,2,1) / √(-2)²+2²+1²)
-⅔=-2x-6-2 / √(4+4+1)
-⅔=-2x-8 / √9
-⅔=-2x-8 / 3

-2=-2x-8
-2x=-2+8
x=6/-2
x=-3