Nomor 3 Diketahui A (-1, 2, 7), B(2, 1, 4) dan C(6, -3, 2). Apabila AB = u dan BC = v, maka hasil dari u . v =... A. 30 B. 22 C. 14 D. 10 E. -2

u =AB
u = B - A
u = (2,1,4)-(-1,2,7)
u = (2+1,1-2,4-7)
u = (3,-1,-3)

v = BC
v = C - B
v =(6,-3,2) - (2,1,4)
v = (6-2,-3-1,2-4)
v = (4,-4,-2)

u.v = (3.4+(-1)(-4)+(-3)(-2)) = (12+4+6) = 22