Question

14. Diketahui vektor a = 2i-3i+xk dan b=i+4i-5k. Jika vektor a tegaklurus vektor b,
maka nilai x = ....
A. 1
B. 2
C. 1
D. -2
E. 0​

Answer 1

Vektor

a = 2i - 3j + xk

b = i + 4j - 5k

tegaklurus → a • b = 0

a • b = 0

2.1 + (-3).4 + x(-5) = 0

2 - 12 - 5x = 0

-10 = 5x

x = -2