Orthogonal Vectors

Question

if u = (6, -9, 6, k) and v = (-2, 3, 2, 1) are orthogonal, find k

a. 51 

b. 3 

c. -3 

d. -51 

e. 0 

Answer 1

the dot product, the scalar product set to zero

of the two vectors indicates orthogonal.

-12-27+12+k=0

k=27

maybe the +12 should be -12