diketahui A=5i-4j+2k B=2i+3j+4k ditanya : A×B

A.B
(5i - 4j +2k) ( 2i +3j +4k)
=10i^2 +15ij +20ik -8ij -12j^2 -16jk +4ik +6jk +8k^2
=10i^2 +7ij +24ik-12j^2 -10jk +4ik +8k^2

(5i-4j+2k)X(2i+3j+4k)
= (5ix5i) (5ix3j) (5ix4k) (-4jx2i) (-4jx3j) (-4jx4k) (2kx2i) (2kx3j) (2kx4k)
= 15k-20j+8k-16i-4j-6i
= 23k - 24j - 22i